Optical information recording employing improved recording power control scheme

ABSTRACT

A disk apparatus performs optical recording onto an optical disk with a record mark by using a light beam modulated in a manner of multi-pulse series, includes. A detection pulse generating part generates a detection pulse to replace the multi-pulse series; and a detection power control part controls the power of the detection pulse to be smaller than the power of the multi-pulse series.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an optical informationrecording, and, also, the present invention relates to opticalinformation recording to be performed on an optical disk media, such asDVD-R (Digital Video or Versatile Disk, Recordable), a DVD-RW(ReWriteable), or the like, having compatibility in format with DVDmedia such as DVD, DVD-ROM of read-only type.

2. Description of the Related Art

A single pulse recording manner as shown in FIGS. 4C and 4D using such alight-emission waveform of an LD (Laser Diode) which is a light sourceto be applied to an optical disk is used as a general record waveformfor CD-R. According to the recording manner, a recording power levelwhich may have two values, or modify a rear edge of a heating pulse forthe shortest data length, and, thereby, attains mark edge (PWM)recording. Information is given to both edges of the record markaccording to such a PWM recording manner.

However, when this single pulse recording manner as shown in FIG. 4C isused as a recording waveform in a large data recording on a DVD-R, etc.,since a record mark may include a distortion into a shape like a teardue to heat storage, or the edge may shift according to a data length,remarkably, as shown in FIG. 4D. Thereby, it may be difficult to providea non-problematic jitter characteristic according to the single pulserecording manner.

For this reason, a multi-pulse recording manner as shown in FIGS. 9C and9D employing such a light-emission waveform from an LD which is a lightsource of the laser to be applied to an optical disk may be used.Thereby, the duty of the heating pulses is adjusted, and, as a result, aproper recording power can be applied such as to result in record marksas shown in FIG. 9D, in which the influence of heat storage may beeasily eliminated, and edge shift at both edges of a record mark can beeffectively reduced.

However, when performing data recording according to the above-describedsingle pulse recording manner, it is possible to know the formationstate of a mark during recording by detecting the luminous energy oflight reflected by the optical disk as a light-receiving signal waveformshown in FIG. 4E for a single pulse interval.

Therefore, even when recording is made while the recording powerchanges, the signal which shows a change in luminous energy of reflectedlight can be obtained. Thereby, data record can be performed withcontrolling to correct deviation of the recording power occurring due toLD power fluctuation, tilt error, media sensitivity unevenness, etc., inaccordance with the state of this change in the luminous energy thusdetected. Such a control scheme is generally referred to as an R-OPC(Running-Optimum Power Control) scheme.

Japanese Patent Publication No. 2-13372 discloses a technique of feedingreflected light back to a laser, and determining whether or notrecording is properly performed based on change along a time axis of thelaser-light detection signal obtained simultaneously with the recording.

However, according to the multi-pulse recording scheme described abovewith reference to FIG. 9C suitable for a large data recording occasion,as shown in FIG. 9E, since the luminous energy of the reflected lightdecreases rapidly by the interception pulse before detecting change inluminous energy of the reflected light due to the recording power, then,the luminous energy of the reflected light increases rapidly by theheating pulse applied again, and, thus, the light-emission state of theLD changes by short time intervals, it may be difficult to detectluminous-energy change for a constant power required in order todetermine the formation state of a mark, and, thus, it may be difficultto properly perform controlling the power by the R-OPC.

With spread of multimedia, media only for reading such as DVD, DVD-ROM,write-once-type media such as DVD-R employing a pigment material as arecording layer, rewriteable media such as DVD-RW employing aphase-change material have been developed.

The information (sectors, in this example) recorded on such DVD mediahas a format as shown in FIG. 10A. According to this format, as shown inFIG. 10A, data (sectors) is continuously recorded at a fixed linedensity on all the tracks of the medium.

In order to prepare an information recording medium having a formathaving a compatibility with media for only reading, information isrecorded at a frequency of a fixed recording channel clock signal whilecontrolling the rotation speed of the medium to be inverse proportion tothe track radius using a CLV (Constant Linear Velocity) scheme as shownin FIG. 10B, and, thereby, the line velocity on the track is made fixed.

However, in order to control the rotation speed of disk by the CLVscheme, to always make the line velocity on the track constant, it isnecessary to change the rotation speed of the disk appropriately. Forthis purpose, a spindle motor which rotationally drives the disk mediumshould provide a large torque so as to perform velocity shift, and thusshould be of a large-sized, expensive type. Moreover, as a time isrequired for completing a predetermined velocity shift, an extra timemay be taken for accessing the disk medium as compared with HDD, MOdrive, etc., for this reason.

In order to avoid necessity of rotation speed shift in recording dataonto a disk medium, a recording format such as that shown in FIG. 11Amay be employed. That is, as shown in FIG. 1C, the frequency of achannel clock signal to be recorded onto the disk medium is controlledas being in proportion to the radius of the track such that thefrequency becomes larger as the track radius increases. Thereby, sincethe recording line velocity is large at the perimeter zone but is smallat the central zone, as shown in FIG. 1D, the recording line density canbe made fixed. It is thus possible to perform information recording onthe disk medium according to a CAV (Constant Angular Velocity) scheme inwhich the rotation speed of the disk medium is fixed as shown in FIG.11B.

Thereby, according to this manner, it becomes not necessary to performcontrol of variable rotational speed of a spindle motor whichrotationally drives the disk medium, and, thus, the spindle motor shouldnot have a large torque, and, thus, may be a small, inexpensive one.Moreover, since no rotation speed change is needed, any extra timeoccurring due to the velocity change is needed, and, thus, it ispossible to shorten the access time needed for seeking a desired trackon the disk medium.

However, the pulse width and recording power of a recording pulse seriesby laser light-emission for recording are optimized with respect to aspecific recording line velocity for a DVD-R medium employing apigment-made recording layer, or a phase-change medium for which,generally, a pit (mark) is formed on the disk medium at a heat mode.Therefore, the state of the mark formed or space therebetween differ ata different recording line velocity. That is, when the pulse width orrecording power differ, the heat energy required for formation of a markmay vary, and, the heating temperature which can be reached varies forevery mark length with respect to the optimum deformation temperaturediffers, and, thereby, average mark length may vary, and optimum pulsewidth may vary. As a result, it becomes not possible to obtain a uniformmark length, and a width of a mark may changes according to a marklength. Thus, tapering of a mark may occur (so-called tear-like mark).Thereby, the jitter characteristic may become problematic.

According to Japanese Laid-Open Patent Application No. 5-225570, inorder to obtain the optimum recording luminous energy for everyrecordable zone of a disk medium for a short time, the optimum recordingluminous energies at specific two recording line velocities are obtainedat an equal recording line velocity for a trial writing zone for atleast two positions, and, by performing inside or outside interpolationon the optimum recording luminous energies for two recording linevelocities obtained by an interpolation routine, the optimum recordingluminous energy for every recording line velocity can be obtained byperforming interpolation processing on the thus-obtained optimumrecording luminous energies.

According to Japanese Laid-Open Patent Application No. 5-274678, inorder to reduce the laser power required for recording without worseningthe jitter characteristic, recording is performed while rotating theoptical disk at a uniform rotational speed, in which the light beamwhich has undergone intensity modulation according to the informationsignal based on the reference clock signals which differ for particularzones is used. Thereby, information is recorded in a zone on theperimeter side on a frequency higher than a frequency on whichinformation is recorded in a zone on the central side. In this method,the light beam is made to have periodical pulses at a frequency which isan integral multiple of the frequency of a reference clock signal foreach zone, wherein the light beam is applied to the disk medium for azone on the perimeter side by a duty ratio of pulse-wise light emissionlarger than that by which the light beam is applied to the disk mediumfor a zone on the central side.

According to Japanese Laid-Open Patent Application No. 10-106008, inorder to provide an optical disk apparatus which can perform informationrecording at a high velocity and with high reliability, an optical disk,an optical head, a synchronized signal generation means, a VCO, a phasecomparison means, a controller, and a record signal generation means areprovided, wherein recording can be performed on the best recordingconditions by appropriately controlling the pulse height and pulse widthof a recording signal according to a recording line velocity.

In these prior arts, the certain setting values of the recording pulsessuch as the duty ratio of pulse-wise light-emission are controlledaccording to a recording line velocity in the CAV scheme. Such a schemeis effective as long as a recording sensitivity distribution of theoptical disk medium is uniform through the entire recording area of thedisk, and an error of the recording power with respect to the settingvalue is kept constant through the entire recording area of the disk.However, for an actual disk medium, in particular, a DVD, it isdifficult to perform recording uniformly through the entire recordingarea of the disk due to unevenness in recording sensitivity on the disk,power variation and/or wavelength variation of the LD (laser diode) duethereto.

That is, since a plurality of fluctuation factors mutually giveinfluences on the characteristics of recorded information (RF signal),such as the jitter characteristic, it may not be possible to performrecording at a uniform signal characteristic throughout the recordingarea of the disk according to the above-described manners in the relatedart. As a result, it may not be possible to obtain the expected effectssatisfactorily. Especially, in a case where the optical disk medium isconcentrically divided into a plurality of recording zones, and controlis made such as to interrupt and restart recording operation repeatedlyacross borders between different zones, so as to cope with difference inrelationship between data transfer rate from a host apparatus and a datarecording rate, it is difficult to perform recording at a uniform signalcharacteristic throughout the recording area of the disk medium.

SUMMARY OF THE INVENTION

An object of the present invention is to enable highly sensitivedetection of the formation state of a mark when employing a multi-pulseseries in pulse-wise light emission for recording.

Another object of the present invention is to enable acquisition ofstable reproduction signal with small jitter.

Another object of the present invention is to calculate a heating powerof a detection pulse easily from a recording power of a multi-pulseseries of light emission, and detect the formation state of a mark withhigh sensitivity, in the above-mentioned case.

Another object of the present invention is to enable maintaining of thejitter characteristic non-problematic, by preventing the data ofrecorded information from being destroyed in the above-mentioned case.

Another objet of the present invention is to enable process any opticaldisk in a recording type different between one employing single pulsefor each mark and the other employing the multi-pulse series for eachmark in the above-mentioned case.

Another object of the present invention is to provide an informationrecording scheme in which an optical disk medium is dividedconcentrically into a plurality of recording zones, the optical diskmedium is rotated, and at the same time, setting of recording pulseseries is changed dynamically. In this case, without performing controlof variable rotational speed of the disk medium, with maintainingcompatibility in recording format with conventional media, and, also,through a simple scheme, recording can be made at a uniform signalcharacteristic throughout the recording area of the disk medium.

Another object of the present invention is to provide an informationrecording scheme by which a recording pulse series is correctedaccording to unevenness of disk characteristic and variation forparticular recording apparatus. Thereby, aggravation of the jittercharacteristic can be prevented, and stable operation of PLL for areproduction clock signal can be attained.

Another object of the present invention is to provide an informationrecording scheme by which, when recording by CAV control is made, simplesetting of a recording pulse series is made for every recording linevelocity, while simple correction of recording power is made so thatrecording for low jitter can be attained throughout the disk medium.

An information recording apparatus, according to the present invention,of performing optical recording on a recording medium with a record markby using a light beam modulated in a manner of multi-pulse series,includes:

a detection pulse generating part (8) generating a detection pulse toreplace a multi-pulse series; and

a detection power control part (29) controlling the power of thedetection pulse to be smaller than the power of the multi-pulse series.

Thereby, although during recording in a manner of basically usingmulti-pulse series, it is possible to detect a condition of markformation with high sensitivity, by replacing a multi-pulse series by adetection pulse.

The apparatus may further include a recording power setting part (29)setting the power of the multi-pulse series such that a ratio betweenthe detection pulse and multi-power series may be fixed.

Thereby, the heating power is controlled for both multi-pulse series fornormal recording and detection pulse for detection so as to maintain aproper mark-formation condition, and, thereby, it is possible to obtaina stable reproduction signal from a thus-recorded information with lowjitter.

The ratio of power of the detection pulse to the multi-pulse series maybe in a range of 0.6 and 0.9.

Thereby, it is easy to calculate the heating power for the detectionpulse from the heating power for multi-pulse series.

The power control part may control the power of recording pulses byusing a recording-condition information value obtained by normalizing anoutput value of a photodetector which receives reflected light from therecording medium during recording operation, by luminous energycurrently emitted by a light-emitting device to the recording medium.

Thereby, it is possible to detect a condition of mark formation withhigh sensitivity even during receiving in a manner of multi-pulse seriespower control.

The detection pulse generating part may replace mark data of amulti-pulse series by the detection pulse.

Thereby, it is possible to maintain the jitter characteristic to anon-problematic condition without destroying original recordinginformation.

The apparatus may further include:

a medium-type detecting part (12) detecting a type of the recordingmedium loaded; and

a selection part (12) selecting as to whether a single pulse or amulti-pulse series is used for forming each record mark, according todetection result of the medium-type detection part.

Thereby, by appropriately switching the heating power for the detectionpulse according to the selection from among different recording manners,such as those of CD-R and DVD-R for example, it is possible to surelyprocess the different types of recording media.

The power control part may control so that the power of the detectionpulse is approximately the same as that of the recording pulse when theselection part determines that a single pulse is used for forming eachrecord mark.

Thereby, the recording power for the detection pulse is the same as thatfor the normal recording pulses in the case of the manner where a singlepulse is used for forming each mark, while the heating power for thedetection pulse is lower than that for the normal recording pulse in thecase of the manner where multi-pulse series is used for forming eachmark. Thereby, it is possible to properly deal with the different typesof recording medium, such as CD-R and DVD-R.

An information recording apparatus, according to another aspect of thepresent invention, of performing optical recording on a recording mediumwith a record mark by using a light beam modulated in a manner ofmulti-pulse series, includes:

a detection pulse generating part (108) generating a detection pulse toreplace a multi-pulse series;

a trial writing part (112) performing trial writing onto a predeterminedzone of the recording medium (102) by using a plurality of differentpowers applied in sequence; and

a detection power control part (119, 123) controlling the power of thedetection pulse according to a light-reception signal obtained fromrecord data made by the trial writing part.

Thereby, by performing trial writing, it is possible to determine theoptimum (heating) power of the detection pulse.

The apparatus may further include a recording power setting part (119,123) setting the power of the multi-pulse series according to alight-reception signal obtained from record data made by the trialwriting part, but the record data is different from record data used bythe detection power control part in position of the predetermined zoneprepared for the trial writing.

Thereby, by performing trial writing, also the optimum heating power ofthe multi-pulse series can be determined.

The trial writing part may perform the trial writing in such a mannerthat:

power is changed stepwise for trial writing onto a first portion of thepredetermined zone for a use by the detection power control part;

power is changed stepwise for trial writing onto a second portion of thepredetermined zone for a use by the recording power setting part; and

the first and second portions are adjacent in position.

Thereby, it is possible to obtain the optimum heating powers of themulti-pulse series and detection pulse at high accuracy from trialwriting performed using a small-sized area of the recording medium.

The trial writing part may perform the trial writing in such a mannerthat:

power is changed stepwise for trial writing onto first portions of thepredetermined zone for a use by the detection power control part;

power is changed stepwise for trial writing onto second portions of thepredetermined zone for a use by the recording power setting part; and

the first and second portions are arranged alternately one by one inposition.

Thereby, it is possible to obtain the optimum heating powers of themulti-pulse series and detection pulse at high accuracy from trialwriting performed using a small-sized area of the recording medium.

The trial writing part may perform trial writing in such a manner that:

trial writing is performed onto a first portion of the predeterminedzone;

trial writing is performed onto a second portion of the predeterminedzone;

trial writing is performed onto a third portion of the predeterminedzone; and

the power to be used for the trial writing onto the third portion isadjusted based on at least a light-reception signal from the record dataof the trial writing made onto one of the first and second portions.

Thereby, it is possible to obtain a target value of recording-conditioninformation for performing R-OPC by recording with multi-pulse series,by using the detection pulse having the optimum heating power.

The trial writing part may perform trial writing in such a manner that:

multi-pulse series is used for performing trial writing onto the secondand third portions of the predetermined zone; and

the thus-used multi-pulse series are replaced by the detection pulses ata predetermined frequency or all of the multi-pulse series are replacedby the detection pulses.

Thereby, it is possible to obtain both the optimum heating power of thedetection pulse and the target value of recording condition forperforming R-OPC by recording with the multi-pulse series, at highaccuracy.

The trial writing part may perform trial writing in such a manner that:

trial writing onto the first, second and third portions is performed ata stretch.

Thereby, it is possible to obtain both the optimum heating powers of themulti-pulse series and detection pulse and the target value ofrecording-condition information for performing R-OPC by recording, onlythrough a stretch of trial writing operation.

The trial writing part may perform trial writing in such a manner that:

a target value for the light-reception signal to be used for recordingonto the recording medium is determined based on the actually obtainedlight-reception signal in performing trial writing onto the thirdportion of the predetermined zone.

Thereby, it is possible to obtain a target value of recording-conditioninformation for R-OPC by recording with multi-pulse series.

At least one of the power of the detection pulse and a ratio in powerbetween the detection pulse and multi-pulse series obtained based on thelight-reception signal obtained from the trial writing may be stored asrecording-condition information.

Thereby, it is possible to record onto the recording medium (opticaldisk) the information for R-OPC obtained through trial writing, for ause at a subsequent occasion.

An information recording apparatus, according to another aspect of thepresent invention, of performing optical recording onto a recordingmedium with a record mark by using a light beam modulated in a manner ofmulti-pulse series, includes:

a detection pulse generating part (108) generating a detection pulse topartially replace the multi-pulse series; and

a power control part (119, 123) controlling the powers of the detectionpulse and multi-pulse series according to at least one of the powers ofthe detection pulse and multi-pulse series or ratio therebetweenpreviously recorded as recording management information of the recordingmedium.

Thereby, by utilizing information for R-OPC operation obtained throughpast trial writing recorded on the recording medium, it is possible toeasily perform R-OPC with high sensitivity.

A recording medium, according to the present invention, to whichinformation can be recorded, includes recording management informationrecorded therein, the recording management information comprising atleast one of the powers for the detection pulse and multi-pulse seriesor ratio therebetween previously recorded as recording managementinformation of the recording medium.

Thereby, by utilizing information for R-OPC operation obtained throughpast trial writing recorded on the recording medium, it is possible toeasily perform R-OPC with high sensitivity.

An information recording apparatus, according to another aspect of thepresent invention, of performing optical recording onto a recordingmedium (202) with a record mark by using a light beam modulated in amanner of multi-pulse series, includes:

a detection pulse generating part (208) generating a detection pulse toreplace a multi-pulse series;

a trial writing part (212) performing trial writing onto the recordingmedium by using a plurality of different powers applied in sequence;

a calculating part (212) calculating modulation degrees of the recordingmedium for the detection pulse based on a light-reception signalobtained from record data made by the trial writing part; and

a detection power control part (219, 223) controlling the power of thedetection pulse based on the thus-obtained data of modulation degrees.

Thereby, it is possible to perform output of the detection pulse withthe optimum heating power, by performing the trial writing.

The detection power control part may determine the power such that thedata of modulation degree obtained from the record data made by thetrial writing part by the power may fall in a range between 0.5 and 0.8as an optimum power.

Thereby, it is easy to calculate the optimum heating power of thedetection pulse.

The detection power control part may control the power of the detectionpulse based on a change of the modulation degree with respect to thepower applied.

Thereby, it is possible to obtain the optimum heating power moreaccurately so as to control a change in modulation degree occurring dueto an influence of surface inclination of the recording medium or thelike.

The detection power control part may determine the power such that thechange in modulation degree of the recording medium obtained from alight-reception signal obtained from record data made by the trialwriting part with the power with respect to the power applied may fallin a range between 1.0 and 2.0 as an optimum power.

Thereby, it is easy to calculate the optimum heating power of thedetection pulse.

The apparatus may further include:

a recording modulation calculation part (212) obtaining data ofmodulation degree of the recording medium for the multi-pulse seriesbased on the light-reception signal; and

a recording power control part (219, 223) controlling the power of themulti-pulse series based on the thus-obtained data of modulationdegrees.

Thus, by performing the trial writing, it is possible to also outputmulti-pulse series with the optimum heating power.

The detection power control part may determine such a power as anoptimum power for the detection pulse as that resulting in themodulation degree approximately equal to the modulation degree obtainedfor the multi-pulse series obtained by the recording modulationcalculating part.

Thereby, it is possible to obtain the optimum heating power of thedetection pulse corresponding to the optimum heating power ofmulti-pulse series.

The detection power control part may obtain a change in modulationdegree of the recording medium obtained by the calculation part withrespect to the power applied;

the recording power control part may obtain a change in modulationdegree of the recording medium obtained by the recording modulationcalculation part with respect to the power applied; and

the detection power control part may determine such a power as anoptimum power for the detection pulse as that resulting in the change ofmodulation degree with respect to the power applied approximately equalto the change of modulation degree obtained for the multi-pulse seriesobtained by the recording modulation calculating part with respect tothe power applied.

Thereby, it is possible to obtain the optimum heating power of thedetection pulse corresponding to the optimum heating power ofmulti-pulse series, at higher accuracy.

The recording power control part may control the power of themulti-pulse series so that a ratio thereof to the power of the detectionpulse controlled by the detection power control part may fall in apredetermined fixed value.

Thereby, even during recording onto the recording medium, the respectiveheating powers of multi-pulse series and detection pulse can be made asoptimum values.

The recording power control part may control the power of themulti-pulse series so that a ratio in power of an optimum value for themulti-pulse series obtained thereby to an optimum value for thedetection pulse obtained by the detection power control part may fall inthe predetermined fixed value.

Thereby, even during recording onto the recording medium, the respectiveheating powers of multi-pulse series and detection pulse can be made tobe optimum values.

An information recording method, according to the present invention, ofperforming optical recording onto a recording medium (202) with a recordmark by using a light beam modulated in a manner of multi-pulse series,includes the steps of:

a) generating a detection pulse to replace a multi-pulse series;

b) performing trial writing onto the recording medium by using aplurality of different powers applied in sequence;

c) calculating modulation degrees of the recording medium for thedetection pulse based on a light-reception signal obtained from recorddata made by the step b); and

d) controlling the power of the detection pulse based on thethus-obtained data of modulation degrees.

An information recording apparatus, according to another aspect of thepresent invention, of performing optical recording onto a recordingmedium (401) with a record mark by using a light beam modulated in amanner of recording pulse series, comprising:

a clock frequency change part (411) changing a recording clock frequencyaccording to a recording line velocity so as to make a recording linedensity uniform; and

a recording power calculating part (414) calculating a recording powerin accordance with the change in recording line velocity by using anapproximation formula,

wherein:

a recording area of the recording medium (401) is concentrically dividedinto a plurality of recording zones;

an end portion of record data recorded on a recording zone of theplurality of recording zones is reproduced;

from a signal characteristic obtained from a thus-obtained reproductionsignal, the approximation formula is corrected so that an ideal signalcharacteristic may be obtained; and

the thus-corrected approximation formula is used for determining therecording power for recording onto a subsequent recording zone.

Thereby, even when the recording line velocity changes by CAV controlsuch that the disk rotation speed may be fixed, and, thus, the optimumcondition on recording is shifted from the setting values, it ispossible to perform correction such that the optimum recording pulsescan be provided for each recording line velocity. Thereby, it ispossible to perform recording throughout the optical disk with uniformcharacteristics. Especially in case where the disk medium is dividedconcentrically into a plurality of recording zones in accordance withdata amounts to be recorded, recording is made on a recording zone afterperforming correction on recording power made based on a result ofreproduction of record data recorded on a preceding recording zone.Thereby, it is possible to perform recording throughout the disk mediumwith uniform characteristics regardless of whether or not the recordingoperation is interrupted and resumed.

Trial writing may be performed onto the recording medium for at leastone of the minimum recording line velocity and maximum recording linevelocity with plurality of recording powers;

the optimum recording power may then be calculated from signalcharacteristics obtained from thus-obtained reproduction signal;

the optimum recording powers for both the minimum and maximum recordingline velocities obtained from either the trial writing or diskinformation previously recorded onto the recording medium may be used,and thus, a first approximation formula for obtaining the recordingpower in accordance with change in the recording line velocity may becalculated;

the first approximation formula may then be used for recording onto amost inner recording zone of the recording medium; and

an end portion of record data thus recorded on the most inner recordingzone of the plurality of recording zones may then be reproduced;

from a signal characteristic obtained from a thus-obtained reproductionsignal, the first approximation formula may be corrected so that anideal signal characteristic may be obtained; and

the thus-corrected approximation formulas may be used for determiningthe recording power for recording onto subsequent recording zones.

Thus, the approximation formulas for the respective recording zones canbe calculated, and thereby, appropriate correction can be made for therespective recording zones. Especially, even when the recording powerchanges due to unevenness of sensitivity across the disk medium,temperature characteristic, mechanical shift and so fourth, it ispossible to appropriately eliminate the thus-occurring difference fromthe optimum recording power. Thus, it is possible to perform recordingthroughout the disk medium in a satisfactory condition. Further, themodulated data can be recorded across boundaries between the receivingzones continuously.

The recording medium may be a pigment-type recording medium employing apigment material as a recording layer thereof.

Accordingly, in case recording is made for each of divided recordingzones onto a so-called write-once type optical disk medium, it ispossible to perform recording with characteristics uniform throughoutthe disk medium.

The recording medium may be a phase-change-type recording mediumemploying a phase-change material as a recording layer thereof.

Accordingly, in case recording is made for each of divided recordingzones onto a so-called erasable type optical dusk medium, it is possibleto perform recording with characteristics uniform throughout the diskmedium.

Modulation or asymmetry may be calculated from the reproduction signaland is used to correct the approximation formula.

Thereby, even when the recording line velocity changes by CAV controlsuch that-the disk rotation speed may be fixed, and, thus, the optimumcondition on recording is shifted from the setting values, it ispossible to perform correction such that the optimum recording pulsescan be provided for each recording line velocity. Thereby, it ispossible to perform recording throughout the optical disk with uniformcharacteristics. Especially in case where the disk medium is dividedconcentrically into a plurality of recording zones in accordance withdata amounts to be recorded, recording is made on a recording zone afterperforming correction on recording power made based on a result ofreproduction of record data recorded on a preceding recording zone.Thereby, it is possible to perform recording throughout the disk mediumwith uniform characteristics regardless of whether or not the recordingoperation is interrupted and resumed. Especially, it is possible toattain recording according to CAV control with a simple and small-sizedcircuit configuration.

An information processing apparatus according to the present inventionmay have the above-described information recording apparatus.

Thereby, in case a lot of data is recorded on the optical disk medium,the optical disk medium may be divided concentrically into a pluralityof recording zones in consideration of difference between the datatransfer rate from the information processing apparatus body to theinformation recording apparatus and the data recording rate of theinformation recording apparatus itself, and thus, control should be madesuch that recording operation is interrupted and resumed across aboundary between different recording zones. Even in such a case,throughout all over the optical disk medium, recording with uniformsignal characteristic can be performed, and, thus, the informationrecording apparatus can be effectively used together with theinformation processing apparatus such as a personal computer.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and further features of the present invention will becomemore apparent from the following detailed description when read inconjunction with the following accompanying drawings:

FIGS. 1A through 1H illustrate waveforms of various signals andconditions of mark formation according to each of embodiments of thepresent invention;

FIG. 2 illustrates a relationship between heating power applied to anoptical disk and modulation degree of RF signal obtained from theoptical disk;

FIG. 3 illustrates a relationship between heating power andrecording-condition information;

FIGS. 4A through 4G illustrate waveforms of various signals andconditions of mark formation in a case of single-pulse recording scheme;

FIG. 5 illustrates trial writing according to a first embodiment of thepresent invention;

FIG. 6 shows a block diagram illustrating a general configuration of anoptical disk apparatus in the first embodiment of the present invention;

FIG. 7 shows a block diagram illustrating part of the configurationshown in FIG. 6 in detail;

FIG. 8 shows an operation flow chart illustrating operation of theoptical disk apparatus according to the first embodiment of the presentinvention;

FIGS. 9A through 9H illustrate waveforms of various signals andconditions of mark formation in an example in which simply a detectionpulse replaces a multi-pulse series;

FIGS. 10A through 10D illustrate a CLV system in the related art;

FIGS. 11A through 11D illustrate a CAV system in the related art;

FIGS. 12A through 12F, 13 and 14 illustrate a PCA of an optical disk andtrial writing performed thereon according to a second embodiment of thepresent invention;

FIG. 15 shows a block diagram illustrating a general configuration of anoptical disk apparatus in the second embodiment of the presentinvention;

FIG. 16 shows a block diagram illustrating part of the configurationshown in FIG. 15 in detail;

FIG. 17 shows an operation flow chart illustrating operation of theoptical disk apparatus according to the second embodiment of the presentinvention;

FIG. 18 illustrates an RMA of an optical disk medium which is utilizedby the second embodiment of the present invention;

FIGS. 19A through 19F illustrate a PCA of an optical disk and trialwriting performed thereon according to a third embodiment of the presentinvention;

FIG. 20 shows a block diagram illustrating a general configuration of anoptical disk apparatus in the third embodiment of the present invention;

FIG. 21 shows a block diagram illustrating part of the configurationshown in FIG. 20 in detail;

FIG. 22 shows an operation flow chart illustrating operation of theoptical disk apparatus in the third embodiment of the present invention;

FIGS. 23A through 23C show waveforms illustrating recording pulse seriesincluding a head heating pulse and subsequent heating pulses inrelationship with other signals according to a fourth embodiment of thepresent invention;

FIG. 24 illustrates characteristics of pulse width ratios and recordingpower ratio with respect to recording line velocity according to thefourth embodiment of the present invention;

FIGS. 25A through 25C show waveforms illustrating recording pulse seriesincluding the head heating pulse and subsequent heating pulses inrelationship with other signals both for the most outer zone and mostinner zone together in a time scale such that the periods of thecorresponding clock pulses are made to be equal to one another,comparatively according to the fourth embodiment of the presentinvention;

FIG. 26A illustrates recording-power dependency of Asymmetry of apigment-type (write-once) optical disk medium;

FIG. 26B illustrates recording-power dependency of Modulation of aphase-change-type (erasable) optical disk medium;

FIGS. 27A and 27B illustrate Asymmetry, Modulation and jitter forillustrating effect of the fourth embodiment of the present invention;

FIG. 28 shows a plan view of a plurality of recording zones dividedconcentrically;

FIG. 29 shows an operation flow illustrating operation according to thefourth embodiment of the present invention;

FIG. 30 illustrates the operation of the fourth embodiment of thepresent invention in which the recording power is corrected for eachrecording zone;

FIG. 31 shows a block diagram illustrating a general configuration of anoptical disk apparatus according to the fourth embodiment of the presentinvention; and

FIG. 32 illustrates a general perspective view illustrating an exampleof application the fourth embodiment of the present invention to apersonal computer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, an information recording system employed by an optical diskapparatus in a first embodiment of the present invention will now bedescribed.

In this information recording system, code data of a DVD-ROM format isrecorded on a recording layer of a DVD-R which employs a pigmentmaterial, for example. As a data modulation type, EFM (Eight to FourteenModulation) Plus modulation code, as shown in FIG. 1B, is used, and,mark edge (PWM: Pulse Width Modulation) recording is performed. A datalength of a mark and space formed on the recording layer of the diskmedium is in a range between 3T and 14T. In the embodiment, theabove-mentioned medium and recording data are used, recording marks areformed on the medium through multi-pulse light emission of asemiconductor laser (LD: Laser Diode), and, thus, information isrecorded onto the DVD-R.

Fundamental recording operation in the case of recording on the opticalmedium employing of a pigment material recording layer is the same asthat described above for the related art. The optimum heating power of amulti-pulse series in this case should be higher than the case of CD-Rwhere a single pulse series is used as a recording waveform, by a factorof approximately 20 through 30 percents (see FIG. 1F). Further, as shownin FIG. 1A, the period of a recording channel clock signal isapproximately 38 nanoseconds, and a recording line velocity is 3.5 m/s.

In this embodiment, as shown in an LD light-emission waveform of FIG.1F, when a mark data length is longer than 9T, the normal multi-pulseseries is replaced by a 7T-length single pulse (detection pulse). Whensuch a recording scheme is applied to a pigment-recording-layer DVD-R,as reflected light from the DVD-R during recording, the luminous energy(RF detection) signal of the reflected light as shown in FIG. 1H isobtained. As for the above-mentioned 7T-length detection pulse, theluminous energy change occurs during mark formation as in theabove-mentioned R-OPC used for the CD-R.

However, if the single pulse having the same heating power as themulti-pulse series were used for the replacement during recording withmulti-pulse series onto the DVD-R, a mark formation state would be suchthat excessive power were applied and the sensitivity for change in thedisk drive apparatus due to aging such as defocus, tilt, power deviationor the like would be degraded. This is because the optimum power for themulti-pulse series is different from that for the single pulse althoughformation of a mark can be made onto the pigment-recording-layer opticaldisk either by the multi-pulse series or the single pulse.

More specifically, as shown in FIG. 2, when a multi-pulse series is usedfor a typical DVD-R by an optimum heating power, the optimum value ofthe heating power Pw1 (heating power of the multi-pulse series) is about12 mW, the degree of 14T modulation by this power becomes around 65%,and, thus, the best jitter characteristic is obtained there.

The heating power Pw2 suitable for the above-mentioned detection pulsecan be approximated by “Pw2=α·Pw1” in this case by multiplying theheating power Pw1 for the multi-pulse series by a coefficient α, whichis 0.75, and the heating power Pw2 at this time is set as a valuesmaller than the heating power Pw1. That is, since the detection pulseused by R-OPC is a single pulse, the power which may result in asatisfactory recording condition can be obtained by multiplying withthis coefficient “α=0.75”.

Since the light-reception power level of the reflected-light signal RFbecomes stable for the portion after the 3T length from the front endduring the interval of the above-mentioned detection pulse, this levelis sampled by a sample-and-hold circuit, and, an RFsmp value (sampledvalue of the reflective-light signal RF) is obtained by an A-Dconverter. Thus, the necessary information concerning the recordingcondition of the optical disk used in the R-OPC operation is obtained.Since this value expresses the luminous energy of the reflected lightfrom the optical disk, the recording-condition information expressingthe recording condition of the optical disk is obtained by“RFopc=RFsmp/Pw2”, through this normalization by the heating power Pw2expressing the light-emission luminous energy applied to the opticaldisk.

As shown in FIG. 3, this recording-condition information RFopc by thesingle pulse shows a negative large inclination around the “Pw2=9 (mW)”obtained by the above-mentioned coefficient α or for the power less thanit. This means that, for this power range, this information has a highsensitivity for various changes/shifts in the drive apparatus due toaging. However, as indicated by the broken line shown in FIG. 1H, if theRFsmp value were obtained in a case where the power same as the heatingpower Pw1 optimum for the multi-pulse series were applied in the singlepulse, the mark would be formed too much, thereby, the 14T modulationlevel and the RF light-reception level during the interval of thedetection pulse would be saturated as shown in FIG. 3 (right side), and,thus, merely little change would occur in response to change/shift inthe heating power.

The coefficient α is set so that the ratio of the heating power Pw1employed for the normal recording operation by the multi-pulse series tothe heating power Pw2 employed for the detection pulse which is a singlepulse may be fixed. By sampling the luminous energy of the reflectedlight for a range of front half between the front end and the 5T lengthof the detection pulse as the detection signal, the condition of markformation at this time can be known. As shown in FIG. 4E, when therecording power is excessively large, the detection signal of thereflected-light level falls more sharply. By detecting this change, itcan be determined that the mark formation is made too much. When therecording power is excessively small, the detection signal of thereflected-light level falls less sharply. By detecting this change, itcan be determined that the mark formation is insufficient.

Before the normal recording operation (before the R-OPC operation),trial writing (OPC) is performed. Specifically, as shown in FIG. 5, themagnitude of the heating power is changed by multiple steps, andrecording a mark of small size is performed for each heating powerlevel. Then, after this trial recording, the optimum heating power Pwo,and the recording-condition information value “RFopco=RFsmp/Pwo” arecalculated from “asymmetry” of the reproduced signal obtained therefrom,previously. When the value of RFopc obtained in the R-OPC operation islarger than this target value RFopc, the light-emission power of the LDis controlled so as to cause it to be larger. When the RFopc value issmaller, the light-emission power of LD is controlled so as to cause itto be smaller. (The reason therefor/logic thereof will be describedlater.) Thus, the heating power Pw2 of the detection pulse is controlledso that the recording condition may be obtained such that the targetvalue RFopco may be reached. Then, by using the above-mentionedcoefficient α by which Pw2 is to be divided, the heating power Pw1 ofmulti-pulse series can also be appropriately corrected. Thereby, thelight-emission power of LD can be controlled based on the mark-formationcondition, and it becomes possible to perform mark formation having auniform state even when the drive apparatus changes in performancethereof due to aging.

In the above-described example, the coefficient α to be multiplied tothe heating power Pw1 for the multi-pulse series is determined as 0.75.However, a different value may be selected for the coefficient αaccording to the pigment material used in the optical disk, setting ofthe recording line velocity, the multi-pulse width, and so forth. Thepossible variable range of the coefficient α for various combinations ofthese factors is preferably a range between 0.6 and 0.9 as a result ofstudy being made, and by choosing the coefficient α within the range,the high sensitivity recording-condition information value RFopc can beobtained.

The above-mentioned detection pulse is inserted so as to replace themark data in recording operation performed basically by the multi-pulseseries. The length of the single pulse as the detection pulse is madeinto (n−2)T for the mark length n so that the mark length formed by thesingle pulse may be equal to that which should be obtained from theoriginal multi-pulse series. Also, the length of this single pulse maybe determined as being optimum according to the pigment material of theoptical disk and the recording line velocity. The position of samplingfor the detection pulse may be determined in consideration of a timeinterval for which the level of the reflected-light signal RF isstabilized enough, and, also, the time interval of the sampling may bedetermined in consideration of the acquisition time of the relevantsampling circuit. A time interval to be taken after each sampling may bedetermined in consideration of aperture delay of the sampling circuit,and, thus, it can be expected that the sampling circuit is realized byan inexpensive configuration and provides a stable operation. Thus,according to this embodiment, even in the case of recording basically bythe multi-pulse series, the detection pulse replaces a multi-pulseseries, and, thus, it becomes possible by multiplying with thecoefficient so that the heating power Pw2 may become smaller, so as toprovide such a heating power of the detection pulse as to obtain thestate of the mark formation during recording, properly.

The optical disk apparatus embodying the above information recordingsystem according to the first embodiment of the present invention willnow be described.

FIGS. 6 and 7 show block diagrams illustrating a circuit configurationof the optical disk apparatus in the first embodiment of the presentinvention. This optical disk apparatus 1 has a pickup 3 including a anLD (not shown in the figures) which is a light source for recordinginformation onto an optical disk 2, an EFM pulse encoder 4 whichgenerates recording data, a recording pulse series control part 5 formodulating light emitted from the LD based on the recording data, and anLD control circuit 6 which makes LD emitting light have a desiredlight-emission waveform based on the recording pulse series controlsignal which the recording pulse series control part 5 outputs.

The recording pulse series control part 5 generates an LD control signalfor driving the LD from the recording data which the EFM pulse encoder 4outputs. This recording pulse series control part 5 includes a recordingpulse series generation part 7, and the recording pulse seriesgeneration part 7 generates multi-pulse series. A detection pulsegeneration part 8 which generates a detection pulse of a single pulsefor the R-OPC operation is also provided in the recording pulse seriescontrol part 5, and the detection pulse to be included in the recordingpulse series is generated. Thus, the LD control signal is generated asmulti-pulse series including the detection pulse, and the LD controlsignal is input to the LD control circuit 6.

The LD control circuit 6 includes LD driving current sources 9, 10 and11 which act as current sources driving the LD. The LD driving currentsource 9 outputs a heating power for peak level of each pulse ofmulti-pulse series, the LD driving current source 10 outputs a heatingpower for a peak level of the detection pulse for the R-OPC operation,and the LD driving current source 11 outputs a bottom power for a bottomlevel of each pulse. The LD control circuit 6 switches or adds theoutput of the LD driving current source 9 or 10 and the LD drivingcurrent source 11 based on the LD control signal, and outputs the resultto the LD, and, thus, produces the LD light-emission waveform (as shownin FIG. 1F) of the multi-pulse series containing the detection pulse.The recording pulse series generation part 7 and the LD driving currentsource 9 act as a multi-pulse series generation part, and the detectionpulse generation part 8 and the LD driving current source 10 act as adetection pulse generation part.

A light-receiving device (not shown in the figures) provided in thepickup 3 receives reflected light from the optical disk 2, and outputs areflected-light signal RF. In a sampling circuit 13, asampling-and-holding operation is performed on the reflected-lightsignal RF at a detection position of a sampling signal, and thedetection pulse in a recording pulse series is sampled and undergoes A-Dconversion by an A/D converter, not shown in the figure, and, thus, asignal RFsmp showing a sampled level of the luminous energy of reflectedlight is obtained.

The level of the reflected light changes according to the luminousenergy emitted from the LD. Therefore, the luminous energy level of thereflected light is divided by the heating power for the detection pulseso that it is normalized, and, thus, a recording-condition informationvalue which reflects a state of formation of the record mark formed onthe optical disk 2 is calculated by the recording-condition informationcalculation circuit 23. Namely, the light-emission luminous energy levelPw of the LD is used for the dividing and thus normalization calculationoperation is performed by a dividing circuit 25.

Then, the recording-condition information value RFopc reflecting thestate of formation of the record mark is calculated. Thisrecording-condition information value RFopc is stored in a RAM or thelike of a system controller 12, for example, as a target value RFopco.The R-OPC operation is started immediately after starting a normalrecording operation, and the recording-condition information value RFopcis calculated as described above at predetermined intervals. Then, sinceit can be determined that the record mark is smaller than an ideal size(thereby the reflectance of the medium there is still kept higher asless luminous energy is applied there and thus the reaction of themedium is insufficient) when the recording-condition information valueRFopc obtained is larger than the target value RFopco as compared withthe above-mentioned target value RFopco by a comparator 24, controllingis made by a first heating power correction circuit 20 of a heatingpower correction circuit 19 to the LD driving current source 9, and,thus, the heating power Pw2 of the detection pulse is increased. On thecontrary, since it can be determined that the record mark is larger thanthe ideal size (thereby the reflectance of the medium there has becomelower as much luminous energy applied there and thus reaction of themedium is too much or excessive) when the recording-conditioninformation value RFopc obtained is smaller than the target valueRFopco, the heating power Pw2 of the detection pulse is corrected sothat it may become smaller. The comparator 24 and the first heatingpower correction circuit 20 act as a first heating power setting part.

Since only the detection pulse is controlled so that the mark formationcondition therefor is controlled properly as described above, theheating power Pw1 of the normal multi-pulse series should also becorrected by dividing the heating power Pw2 of the detection pulsecorrected as mentioned above by the above-mentioned predeterminedcoefficient α by a second heating power correction circuit 21. Thesecond heating power correction circuit 21 acts as a second heatingpower setting part.

By carrying out the above-described operation of R-OPC, the heatingpower Pw1 for the multi-pulse series and the heating power Pw2 for thedetection pulse are well controlled so that the ratio therebetween iskept constant as the predetermined coefficient α.

Therefore, since thus the mark formation condition for each of theheating powers Pw1 and Pw2 is maintained as the optimum recordingcondition, even when any change in performance/characteristic of thedriving apparatus occurs, a non-problematic jitter characteristic willbe able to obtained from the reproduction signal.

It is possible that a microcomputer such as the system control 12 mayperform functions of part or all of the sampling circuit 13, therecording-condition information operation circuit 23, the heating powercorrection circuit 19, etc.

With reference to FIG. 8, the trial writing operation and subsequentnormal recording operation of the above-mentioned optical disk apparatus1 according to the first embodiment of the present invention will now bedescribed. As shown in the figure, first, from a preformat of theoptical disk 2, pulse width setting information for multi-pulse seriesand a recommended heating power value are read (in a step S1), thepredetermined coefficient α is determined (in a step S2), and theheating power Pw2 for the detection pulse is calculated (in a step S3),as described above. Then, since the actual heating power may have anerror depending on a particular driving apparatus, the target valueRFopco of the recording-condition information value RFopc is calculated(in a step S5) by detecting the optimum recording power Pwo through thetrial writing operation as described above (in a step S4).

Then, normal recording (R-OPC operation) is started (in a step S6), andsteps S7 through S10 are performed. That is, a multi-pulse series isreplaced by the detection pulse as mentioned above, and therecording-condition information value RFopc is calculated throughnormalization by the dividing circuit 25 (in a step S7). The comparator24 compares this recording-condition information value RFopc with thetarget value RFopco (in a step S8). Then, when both are not equal to oneanother, the heating power Pw2 of the detection pulse is corrected bythe first heating power correcting circuit 20 so as to change it into apower Pw2′ (in a step S9), as described above, and, then, a power Pw1′is calculated by dividing the value of Pw2 by the coefficient α by thesecond heating power correction circuit 21, and the thus-obtainedheating power Pw1′ is set for multi-pulse series (in a step S10).Processing of steps S7 through S10 is performed until the end address ofrecording data is reached (No of the step S11). Thus, the heating powerPw2 for the detection pulse is corrected in the R-OPC operation, and,then, the dividing operation by the predetermined coefficient α isperformed, thus, the heating power for normal multi-pulse series is alsocorrected as “Pw1=Pw2/α”. Thereby, the heating powers Pw1 and Pw2 aremaintained of having the fixed ratio therebetween.

It is possible to configure the optical disk apparatus 1 so that theapparatus 1 can handle either CD-R or DVD-R by selecting either one, aswill now be described. That is, normally, in a case of the optical diskapparatus 1 which can carry out recording and reproduction on each of CDfamily and DVD family, after the optical system and signal processingsystem of the pickup determine the disk type of the currently loadeddisk, they are switched appropriately so that they can properly processthe CD family or DVD family according to the determination.

With regard to the recording pulse series (for normal recordingoperation), identification is performed as to whether the currentlyloaded disk is CD-R or DVD-R (this may be determined by reading thepreformat in the above-mentioned step S1). This function corresponds tothat of a type detection part. Then, switching is made for the recordingpulse series based on the result of this identification determination.That is, when the currently loaded optical disk is a CD-R, single pulserecording scheme is selected, recording is performed by the single pulserecording scheme as shown in FIGS. 4C and 4D, for example, in which asignal pulse is used for forming each record mark. On the other hand,recording is performed by multi-pulse series in which a multi-pulseseries is used for forming each record mark, as shown in FIG. 1C, at atime of DVD-R.

Then, according to the identification of disk type and its recordingpulse series for each type of optical disk, the heating power of thedetection pulse when operating R-OPC is appropriately switched. That is,at a time of CD-R, the normal heating power and the heating power of thedetection pulse by the single pulse series are made coincident. On theother hand, in the case of DVD-R, the normal heating power for themulti-pulse series is multiplied by the predetermined coefficient α,and, thereby, the heating power of the detection pulse may becomesmaller than the normal heating power for the multi-pulse series.

Moreover, also, in case of employing multi-pulse series and carrying outnormal recording for CD-R, or in cases of employing single pulses andcarrying out normal recording for DVD-R, it is determined as to whetheror not the heating power of recording pulses is multiplied by thepredetermined coefficient so as to obtain the heating power for thedetection pulse, not according to the disk type of the currently loadedoptical disk, but according to the type (multi-pulse series of singlepulses) of recording pulses used for normal recording.

Thus, by performing switching as described above, it becomes thuspossible to detect the record-mark recording condition at a highsensitivity for particular disk types and particular types of recordingpulses, and, thereby, it becomes possible to correct the heating powerappropriately so that the jitter problem which otherwise occurs due tochange in performance/characteristic of the driving apparatus may besolved.

A configuration of the optical disk 2 suitable for the above-describedembodiment, and, also, a method of detecting the mark-formationcondition at high accuracy will now be described.

A recording layer of the optical disk 2 is such that optical change iscaused by thermal decomposition due to laser-light application and/orsubstrate deformation occurring thereby, and, thereby, a record mark isformed. When recording on the optical disk by marks formed due to theabove-mentioned heat mode is performed, change in luminous energy of thereflected light has a very high sensitivity, and therefore, this type ofdisk medium is suitable for the above-described embodiment of thepresent invention.

Typically, an organic pigment may be used for the recording layer, suchas a polymethine pigment, dye of a naphthalocyanine family, aphthalocyanine family, a squalirium family, a croconium family, apyrylium family, a naphthoquinone family, an anthraquinone family(indanthrene family), a xanthene family, a triphenylmethane family, anazulene family, a tetrahydrocorrin family, a phenanthrene family, atriphenothiazine family, a metal complex compound thereof, etc. may beused, for example. These pigments may be mixed or laminated with otherorganic pigment, metal, metal compound and/or the like for the purposeof improving the optical characteristic, recording sensitivity, signalcharacteristic, etc., thereof. Examples of the metals and metalcompounds applicable thereto are In, Te, Bi, Se, Sb, Ge, Sn, Al, Be,TeO₂ and SnO, As, Cd, etc. It is also possible to use them in a form ofdistributed mixture or lamination.

Formation of the recording layer may be performed by a well-knownmethod, such as vacuum deposition, sputtering, CVD, a solventapplication, or the like, When employing the solvent application method,the above-mentioned dye etc. can be dissolved into an organic solvent,and then, it is applied by a common coating method, such as spraying,roller coating, dipping, spin coating, etc. When the optical disk formedas described above is used in the above-described embodiment of thepresent invention, the luminous energy of reflected light therefromreflects the condition of the mark formation during recording with highsensitivity enough by the detection pulse in the form of the singlepulse as described above. Therefore, by using the above-mentionedoptical disk in the embodiment of the present invention, correction ofthe recording heating power according to change ofperformance/characteristic such as defocus, tilt, temperature dependencyof LD output, etc. of the driving apparatus can be attained. Thereby, itis possible to perform recording operation in a satisfactory markformation condition such as to result in non-problematic jittercharacteristic throughout the recording area of the disk medium.

Moreover, although the rate of the optical change during mark formationat the time of recording changes according to the above-mentionedrecording material, film thickens of the recording layer, etc., it ispossible to detect the mark formation condition with high sensitivity byappropriately setting the detection position of the single detectionpulse at which the luminous energy of the reflected light is detectedaccording to the above-mentioned rate of the optical change.

In addition, for other recording material for which mark formation isperformed by a heat mode, change of the luminous energy of reflectedlight during recording has almost the same tendency. Therefore, theabove-described method according to the present invention can also beapplied thereto.

As mentioned above, if a normal multi-pulse series were merely replacedby a single detection pulse as shown in FIG. 9F, the luminous energysignal of the reflected light (reflected-light signal RF) such as thatshown in FIG. 9H would be obtained. This detection pulse would reflectthe luminous energy change occurring according to the condition of markformation in the same manner as in the above-mentioned R-OPC operationapplied to a CD-R system.

However, as the replacement were made merely by the single pulse havingthe same heating power as that of normal multi-pulse series, anexcessive power would be applied to the disk medium, and, thereby, themark formation condition would be such that the mark would be formed tobe so large as to be reduced in reflectance of the medium and thusreduced in the detection level as shown in FIG. 9H. Thereby, asdescribed above with reference to FIG. 3, it would be not possible toobtain sufficient information from the reflected-light signal as thedetection level would not be sufficiently sensitive for detecting adegree of aging of the driving apparatus such as defocus, tilt,temperature dependency of heating power, and so forth, by the reasondescribed above for DVD-R or the like having the recording layer made ofpigment, in general.

A second embodiment of the present invention will now be described.

In the second embodiment, same as in the above-described firstembodiment, immediately before starting normal recording operation,trial writing (OPC) is performed as preparation work before the R-OPCoperation. As shown in FIG. 12A, a PCA (Power Calibration Area) isprovided in the optical disk at the inner or central portion thereof,and, by using this area, many number of times of trial writing can bemade. As shown in FIG. 12B, for example, one trial writing is made for1ECC=16 sectors which is a recording unit. Thereby, when one step isassigned to 1 sector as a minimum unit, it is possible to change theheating power stepwise and to perform trial writing of 16 steps at themaximum.

Then, as shown in FIG. 13, first, the heating power of multi-pulseseries is changed by six steps in total, and trial writing is made onto6 sectors (which zone is referred to as a first trial writing zone).Then, the heating power of the detection pulse used in the R-OPCoperation is similarly changed by six steps in total, and trial writingis made onto 6 sectors (which zone is referred to as a second trialwriting zone). Thus, the zones of total 12 sectors are used by the trialwriting.

Then, by performing reproduction operation on the above-mentioned firsttrial writing zone, a maximum level Ipk, a minimum level Ibtm, and anaverage level Idc are detected, as shown in FIG. 12C. Then, as shown inFIG. 12E, ‘modulation degree’ on the maximum amplitude“m1=(Ipk−Ibtm)/Ipk” is calculated, and is held, and, also, as shown inFIG. 12D, ‘asymmetry’ on the maximum amplitude Imax and average valueIdc is calculated “β=[(Ipk−Idc)−(Idc−Ibtm)]/(Ipk−Ibtm)” and is held.Furthermore, as shown in FIG. 12D, an approximation formula iscalculated from these plotted points, and the optimum heating power Pw1ofor the multi-pulse series such that β=0 is calculated. Furthermore, themodulation degree ml at this time is obtained.

Then, as shown in FIG. 12E, the modulation degree m2 on the maximumamplitude Imax is calculated from the reproduction signal obtained fromthe second trial writing zone, by the same methods of level detectionand calculation. Then, the optimum heating power Pw2o for the detectionpulse is calculated from these modulation degrees m1 and m2. For thedetails of calculation, description will be made later.

In this method, the first trial writing zone and the second trialwriting zone can be set adjacent and regarded as one zone, and, thus,recording operation and reproduction operation therefor can be attainedby single operation each.

The method of obtaining the optimum heating powers for the multi-pulseseries and detection pulse by trial writing will now be described indetail.

Generally speaking, the modulation degree falls in a range between 0.6and 0.7 when recording is made by the optimum heating power for DVD-R,using multi-pulse series. In contrast thereto, when recording is made bythe optimum heating power using single pulse, the modulation degreefalls in a range between 0.7 and 0.8, in general. Thereby, as a firstprocess, the heating power can be used as the optimum heating power suchthat the modulation degree m2 of the above-mentioned detection pulseshould be equal to or larger by approximately 0.1 than the modulationdegree ml obtained from the optimum heating power for the multi-pulseseries. Therefore, for the optical disk manufactured according to thestandard, the heating power which results in the modulation degreepredetermined for a particular type of the optical disk or a particulartype of the optical disk apparatus from among a plurality of modulationdegrees in a range between 0.5 and 0.8 for the detection pulse ispreviously set as the optimum heating power.

Then, as a second process, for the optimum heating power for performingnormal recording by using multi-pulse series, the modulation degree mland the asymmetry β obtained by the above-mentioned trial writing areused, the optimum heating power Pw1o for the multi-pulse series suchthat β=0 is calculated, and, also, the modulation degree mlo on thisoptimum heating power is calculated. Also for the detection pulse,similarly, the optimum heating power Pw2o is calculated for thedetection pulse on the modulation degree m2 which is approximately equalto the modulation degree mlo on the above-mentioned optimum heatingpower for the multi-pulse series, from the modulation degree m2 obtainedby the trial writing.

As a third process, as shown in FIG. 12F, for the purpose of eliminatingadverse influence of change in the modulation degrees m1 and m2 due tosurface inclination of the optical disk or the like, by using not themodulation degree itself, but change in the modulation degree withrespect to the heating power, i.e., “γ=(dm/dPw)×(Pw/m)” obtained fromrelationship between the modulation degree and heating power obtainedfrom trial writing is used. Thereby, it is possible to improve thedetection accuracy. That is, it can be determined that the detectionsensitivity is satisfactory when the change in the modulation degree γobtained from trial writing for the detection pulse falls within aproper range. For example, the detection sensitivity is too small whenγ<1.0, while, since the heating power is so low that the mark formationis not stabilized yet, and, thus, rather detection error becomes larger,when γ>2.0. Accordingly, a predetermined heating power such as toprovide a predetermined change in modulation degree γ in the rangebetween 1.0 and 2.0 should be used as the optimum heating power.

As a fourth process, in order to perform normal recording by usingmulti-pulse series, the optimum heating power Pw1o for multi-pulseseries such that β=0 is calculated from the above-mentioned modulationdegree m1 and asymmetric β obtained from trial writing, also, anapproximation formula for the modulation degree and heating power isderived from the modulation degrees m1 on respective heating powers,and, then, the change in modulation degree with respect to the heatingpower γ1o on the optimum heating power Pw1o is calculated. Similarly,for the detection pulse, by trial writing, the modulation degree m2 ofthe reproduction signal is obtained and held, and, then, the optimumheating power Pw2o for the detection pulse on the change in modulationdegree with respect to the heating power γ2o obtained from theapproximation formula of the modulation degree and heating power whichis approximately equal to the above-mentioned change in modulationdegree with respect to the heating power γ1o for the multi-pulse seriesis calculated. By this process, it is possible to obtain the optimumheating power for normal recording by using multi-pulse series and theoptimum heating power for the detection pulse for OPC, with a littledetection error even due to change in recording condition.

A specific process of calculating the change in modulation degree withrespect to heating power γ and Pw to be obtained in the above-mentionedthird and fourth processes will now be described. First, from aplurality of sets of characteristic data between the modulation degreeand heating power obtained from trial writing, calculation is performedby the following quadratic approximation formula:

m=a×Pw ² +b×Pw+c

where a, b and c denote constants. The approximation manner may be of acommon approximation form, such as polynominal approximation, and, anapproximation formula of more than quadratic one can result incoincidence between an actually measured value and the thus-calculatedvalue.

Then, since “γ=dm/dPw×m/Pw” as mentioned above, and, “dm/dPw=2×a×Pw+b”,the following formula can be obtained:${Pw} = \frac{{{- b} \times \left( {\gamma - 1} \right)} \pm \sqrt{{b^{2} \times \left( {\gamma - 1} \right)^{2}} - {4 \times a \times \left( {\gamma - 2} \right) \times c \times \gamma}}}{2 \times a \times \left( {\gamma - 2} \right)}$

By performing the above-mentioned calculation, the objective Pw can beobtained which is the plus solution of the above-mentioned formula.

Although calculation through a quadrature approximation formula of γ andPW may be calculated after calculating each γ, the approximated valuemay likely to have an error from the actual measured value in this case,it is preferable to approximate the modulation degree m, as mentionedabove.

According to the above description, as shown in FIG. 13, the trialwriting for each of the multi-pulse series and the detection pulse usestotal 6 sectors for increasing the heating power by six steps. Further,the first and second trial writing zones are separate completely.However, it is also possible that, as shown in FIG. 14, total 12 sectorsare used in which, setting of the recording pulse is switched, and thefirst and second trial writing operations are performed alternatelysector by sector. In this case, also in the reproducing operation, bydetermining that the first and second trial writing zones are switchedalternately sector by sector, it is easy to perform detection operationproperly for the first and second trial writing zones. At this time,through the entire area of the first and second trial writing zones, themodulation degree does not change sharply, but approximately increasesmonotonously. Therefore, it becomes possible to reduce a change amountat a zone at which the heating power is minimum, and the calculationaccuracy for each optimum heating power becomes better.

Although the above-mentioned PCA of the optical disk includes total 16sectors, and, 4 sectors are left after the 12 sectors are used asmentioned above as the first and second trial writing zones, as shown inFIG. 14, and, these 4 sectors are used for a third trial writing zonefor setting the target value RFopco of the recording-conditioninformation used for the actual R-OPC operation, as shown in FIGS. 12B,13 and 14. Specifically, the second optimum heating power Pw2o for thedetection pulse is obtained from the reflected-light signal RF obtainedfrom the first and second trial writing zones, and, this heating poweris used for performing trial writing on this third writing zone.Thereby, the target value RFopco is obtained.

Thus, for recording on the third trial writing zone, the result of trialwriting performed on the first and second trial writing zones isreflected, and, thus, it is not possible to perform the recordingsimultaneously. However, in order to perform the third trial writing asa part of a single trial writing operation, the third trial writing zoneof 4 sectors are located adjacent to the first and second trial writingzones, and total 16 sectors are used for the trial writing as a whole.Since the purpose of this third trial writing is to perform detection ofmark-formation condition during actual recording operation properly, thethird trial writing may be performed by basically multi-pulse series,and, the multi-pulse series is replaced by the detection pulse accordingto a frequency of performance of the detection. Alternatively, all therecording pulses may include only the detection pulses, results of manytimes of detection by sampling, which will be described later, are held,and the average thereof is obtained, thereby the accuracy of thedetection level and target value of the recording-condition informationbeing able to be improved.

Moreover, actual trial writing operation is performed such that,subsequent to recording on the first trial writing zone by usingmulti-pulse series, recording on the second trial writing is performedby using multi-pulse series but partially replaced by the detectionpulse adjacently. Then, reproduction operation can be performed on thefirst and second trial writing zones collectively at once. Therefore,one trial writing operation can be performed within a short time,needing only a small-sized zone on the optical disk, in which highlyprecise trial writing for multi-pulse series and the detection pulse canbe performed. After calculating the optimum recording power for themulti-pulse series and that for the detection pulse as described abovefrom the above-mentioned reproduction signals, the recording pulseseries which contain the detection pulse are used for performingrecording on the third trial writing zone, subsequently, adjacent to thefirst and second trial writing zones.

An optical disk apparatus according to the above-described secondembodiment of the present invention will now be described, whichperforms the above-described scheme.

FIGS. 15 and 16 are block diagrams showing a general configuration ofthe optical disk apparatus in the second embodiment of the presentinvention. The circuit configuration shown in FIG. 15 is the same asthat shown in FIG. 6 of the first embodiment, and the duplicateddescription thereof is omitted.

Operation of the trial writing is performed as follows:

Necessary data such as values of heating power is read out frompreformat previously recorded onto the optical disk 102, or previouslystored in a ROM of a system controller 112 which controls the entiretyof the optical disk apparatus 101. Then, by using the data, an LDcontrol signal is generated by a recording-pulse-series generating part107 and a detection-pulse generation part 108. A light beam emitted froman LD based on this LD control signal is applied to the optical disk102, and thus, the trial writing is performed as describe above. Thereflected light is received by a light-receiving device (not shown inthe figures) of a pickup 103, and, thereby, the reflected light from theoptical disk 102 at this time for the trial writing is converted into areflected-light signal RF, and is outputted to a sampling circuit 113.

From the reflected-light signal RF obtained from the first trial writingzone on which recording is performed by multi-pulse series, withreference FIG. 16, the maximum level Ipk is held by a peak hold circuit114 of the sampling circuit 113, the minimum level Ibtm is held by thebottom hold circuit 115, and, then, the average level Idc obtainedthrough a high-frequency region removal process by a low-pass filter 116is detected. These signals are sampled by a first sample-and-holdcircuit 117 at predetermined detection positions so as to providesampled signals, respectively, and, the thus-obtained sampled levels areconverted into a digital signal by an A-D converter (not shown in thefigure).

In the same manner, from the reflected-light signal RF obtained from thesecond trial writing zone on which recording is performed by thedetection pulse, the maximum level Ipk is held by a peak hold circuit114 of the sampling circuit 113, the minimum level Ibtm is held by thebottom hold circuit 115, and, then, the average level Idc obtainedthrough a high-frequency region removal process by a low-pass filter 116is detected. These signals are sampled by a second sample-and-holdcircuit 118 at predetermined detection positions so as to providesampled signals, respectively, and, the thus-obtained sampled levels areconverted into a digital signal by an A-D converter (not shown in thefigure).

A first power calculation circuit 120 and a second power calculationcircuit 121 calculate the optimum heating power Pw1o for the multi-pulseseries and the optimum heating power Pw2o for the detection pulses bythe above-described processes. In the trial writing, trial writing isperformed on the third trial writing zone by the heating power Pw2ocalculated by the second power calculation circuit 121. Then, thereflected light from the optical disk 102 obtained during the recordingoperation is received by the light-receiving device, not shown in thefigure, and, the thus-obtained detection signal is sampled and held bythe sampling circuit 113 as described above.

Since this detected signal level changes according to the luminousenergy emitted from the LD at the time, the signal RFsmp obtained at thetime is normalized as a result of being divided by the light-emissionluminous energy level Pw2 through a dividing circuit 125 of arecording-condition information calculation circuit 123, and, thus, arecording-condition information value RFopc which reflects the markformation condition is calculated. This recording-condition informationvalue RFopc obtained during the trial writing is stored in a RAM of thesystem controller 112, or the like, as a target value RFopco.

A comparator 124 compares the magnitude of this target value RFopco withthe recording-condition information value RFopc obtained atpredetermined intervals as described above. The second power calculationcircuit 121 calculates the optimum heating power Pw2o for the detectionpulse according to the result of this comparison each time.

A heating power correction circuit 122 outputs the optimum heating powerPw1o or Pw2o calculated by the first power calculation circuit 120 andthe second power calculation circuit 121 to an LD driving current source109 or 110, and the LD driving current sources 109 or 110 performscontrol such that the LD emits the optimum heating power Pw1o or Pw2o.

With reference to FIG. 17, the trial writing operation and subsequentnormal recording operation will now be described. First, trial writingis performed onto the first and second trial writing zones as describedabove (in a step S101). Then, sampling and holding of thereflected-light signal RF on this recording is carried out as describedabove by the sampling circuit 113 (in a step S102). Then, the optimumheating powers Pw1o and Pw2o are calculated by the first and secondpower calculation circuits 120 and 121 by using the data sampled andheld as mentioned above (in a step S103). Then, trial writing isperformed onto the third trial writing zone by the thus-obtained heatingpower Pw2o (in a step S104). Then, as described above, therecording-condition information value RFopco is obtained as describedabove from the results of the above-mentioned recording, this value isset as the target value RFopco (in a step S105), and thus, a series oftrial writing is ended. The steps S101 through S105 is a trial writingprocess as a whole, and the step S105 is a target value acquisitionprocess.

After the end of trial writing, the R-OPC operation is started afterstarting of the normal recording onto the optical disk 102, and, then,the recording-condition information value RFopc is obtained as describedabove at predetermined intervals (in a step S106). The comparator 124compares the target value RFopco with the current recording-conditioninformation value RFopc each time (in a step S107).

When the current recording-condition information value RFopc is largerthan the target value Ropco, that is, RFopc>RFopco, it can be determinedthat the record mark formed is left smaller than an ideal size bydetermination of the step S107, and, thus, the heating power of thedetection pulse is increased (in a step S108). In contrast thereto, whenthe current recording-condition information value RFopc is smaller thanthe target value Ropco, that is, RFopc<RFopco, it can be determined thatthe record mark formed has already become larger than the ideal size bydetermination of the step S107, and, thus, the heating power of thedetection pulse is decreased (in a step S109). When the currentrecording-condition information value RFopc is equal to the target valueRFopco, that is, RFopc=RFopco, the heating power for the detection pulseis maintained as the current value (in a step S110).

Thereby, only the detection pulse is controlled to have a proper heatingpower according to the condition of mark formation. Accordingly, theheating power for the normal multi-pulse series is then corrected by thefirst power calculation circuit 120 by performing operation such thatthe thus-corrected heating power Pw2′ for the detection pulse is dividedby the predetermined heating power ratio α. That is, while the detectionpulse is used for detecting excess or shortage in recording conditionduring the normal recording, and the heating power of the detectionpulse is appropriately corrected according to the result thereof toPw2′, and, also, the heating power for the multi-pulse series isappropriately corrected to Pw1′ (in a step S111). Each time the heatingpower for the detection pulse is corrected as described above, theheating power for the multi-pulse series is also corrected such that“Pw1′=Pw2′/α”.

The above processing of the steps S106 through S110 is performed untilthe end address of recording data is reached (in a step S112).

Thus, as recording to the optical disk 102 is performed while the R-OPCoperation always thus corrects the heating powers for the multi-pulseseries and detection pulse, the heating powers can be always kept as theoptimum ones even when various change in performance of the drivingapparatus due to aging or the like occurs. Thereby, it is possible toattain recording on the optical disk 102 with uniform and low jitter

As shown in FIG. 18, the recordable optical disk 102 such as a DVD-R, orthe like has a recording management area (RMA) to which recordingmanagement data (RMD) obtained by the trial writing is recorded, otherthan the trial writing area (PCA). This RMD recorded onto the RMA canhave various information concerning recording written thereto, such asdisk ID, drive ID, a recording strategy setting, record date/time,address of trial writing, optimum heating power, etc.

Generally, as the R-OPC is designed for the particular disk drivingapparatus arbitrarily, information concerning the R-OPC operation is notrecorded in the RMA. Therefore, it is necessary to perform trial writingto obtain the above-mentioned optimum heating powers for the multi-pulseseries and detection pulse and the above-mentioned recording-conditioninformation onto the optical disk 102 each time.

Therefore, the optimum heating power for multi-pulse series and theoptimum heating power for the detection pulse obtained by the abovetrial writing are made to be written in as information of the RMA. Theposition thereof to be used for this purpose may be a part of apredetermined area prepared for drive ID data such as serial numberand/or model number of the driving apparatus, or an area for reserveddata to be newly allocated therefor.

Thus, the above-mentioned information concerning R-OPC may be writtenthere such that, the optical disk 102 on which the trial writing hasbeen performed and the specific optical disk apparatus 101 aredetermined, and, thereby, the specific combination can be identifiedfrom the thus-written information. Furthermore, instead of the optimumheating power for multi-pulse series and the optimum heating power forthe detection pulse themselves, the ratio of the optimum heating powerfor multi-pulse series and the optimum heating power for the detectionpulse calculated from the data obtained by trial writing, Pw2o/Pw1o, maybe written there.

One example of R-OPC performed using the information recorded on theabove-mentioned RMA will now be described.

That is, the optical disk apparatus 101 recognizes the optical disk 102,and reads the latest recording management information written in the RMAconcerning the results of the trial writing performed in the past, aspreparation for actual recording. From this record managementinformation, the information to be used for R-OPC operation is selectedwritten in a previously allocated position. Then, the optical diskapparatus 101 determines as to whether or not the information concerningthe R-OPC operation has been written in the optical disk 102 by the sameoptical disk apparatus 101 in the past. When it has not been written inthe past, the above-mentioned trial writing can newly be performed,thereby, the optimum powers for multi-pulse series and the detectionpulse and the recording-condition information value are obtained, and,thereby, the R-OPC operation can be performed.

On the other hand, when the information concerning the R-OPC operationhas been written in the past, the ratio Pw2o/Pw1o which is calculatedfrom the optimum powers for multi-pulse series and detection pulse readtherefrom, or the ratio of the optimum heating powers Pw2o/Pw1o readtherefrom is held in a RAM, or the like of the system controller 112.Trial writing to be newly performed in this case is only such that,thereby, the optimum heating power for multi-pulse series is obtained,and then, the optimum heating power for the detection pulse can becalculated by carrying out the multiplication of the ratio of theoptimum heating powers held in the RAM or the like. Then, by performingtrial writing for obtaining the recording-condition information valueusing this optimum heating power, all the information needed for theR-OPC operation is obtained. Thus, by reading the information concerningR-OPC operation from the RMA, trial writing for the detection pulse canbe omitted, and, thereby, the area to be used in the PCA can be madeinto a small-sized one.

Moreover, it can also become possible that only trial writing forobtaining the recording-condition information value RFopc is performedusing the information concerning R-OPC operation read from the RMA, and,thereby, the trial writing can be simplified further.

A third embodiment of the present invention will now be described.

In the third embodiment, as shown in FIGS. 19A through 19F, differentfrom the above-described second embodiment described with reference toFIGS. 12A through 12F, 8 sectors of the PCA are used for the first trialwriting for multi-pulse series, the other 8 sectors thereof are used forthe second trial writing for the detection pulse, and no third trialwriting is performed. The other configuration and operation of the trialwriting of the third embodiment are the same as those of the secondembodiment, and duplicated description thereof is omitted.

Furthermore, as shown in FIGS. 20 and 21, the block configuration of anoptical disk apparatus 201 in the third embodiment of the presentinvention is the same as that of the above-described second embodimentdescribed with reference FIGS. 15 and 16. Also, as shown in FIG. 22, theoperation of the third embodiment is the same as that of the secondembodiment described above with reference to FIG. 17, except that, inthe third embodiment, the third trial witting is omitted as mentionedabove, each of the first and second trial writing zones includes 8sectors as mentioned above, and the target value RFopco is obtainedthrough trial writing made onto the first and second trial writingzones. The other configuration and operation of the third embodiment isthe same as those of the second embodiment, and duplicated descriptionthereof is omitted.

A fourth embodiment of the present invention will now be described.

First, same as in the above-described embodiments, a record markcorresponding to each mark data length nT (n denotes an integer in arange between 3 and 14, and T denotes a recording clock period) isformed by a plurality of heating pulses (multi-pulse series) for thepigment-recording-layer type (pigment-type) optical disk.

As a basic setting of the above-mentioned plurality of heating pulsesfor each mark data length nT, the number of pulses, n−x (x is 1 or 2),and the ratio of the pulse width of the top pulse to the recording clockperiod, Ttop, the ratio of the pulse width of the subsequent pulses tothe recording clock period, Tmp, and the ratio of the pulse width of thelast pulse to the recording clock period, Ttail are determined.Moreover, there are a recording power Pw of the heating pulse part forforming a mark and a bias power Pb for forming a cooling pulse partduring the mark and a space between marks. The condition of markformation is strongly affected by the recording line velocity Lv andthus has a strong correlation therewith. That is, as the recording linevelocity becomes larger, the optimum value of recording power becomeslarger, as well-known in the art. Moreover, there is a ratio inrecording power “σ=P max/P min” of the optimum recording power P max forthe most outer (peripheral) zone of the optical disk (namely, for themaximum recording line velocity) to the optimum recording power P minfor the most inner (central) zone of the optical disk (namely, for theminimum recording line velocity), which shows recording-line-velocitydependency on the disk.

In the fourth embodiment of the present invention, setting is made indetail for the above-mentioned ratio Ttop of the head heating pulsewidth to the recording clock period T, the ratio Ttail of the pulsewidth of the last heating pulse to the recording clock period T, and theabove-mentioned ratio σ of the recording powers, according to therecording line velocity. Especially, finely correction is made on therecording power (heating power).

When recording control is made by the above-mentioned CAT scheme for apigment-type (pigment-recording-layer type) DVD disk of 120-mm diameter,generally speaking, the recording line velocity at the most inner zoneof the disk is approximately 3.5 m/s, and is approximately 8.5 m/s forthe most outer zone. The recording clock frequency is approximately 63.7MHz for the most outer zone, and is approximately 26.2 MHz for the mostinner zone of the disk. Thereby, difference in the recording linevelocity is approximately 2.4 times therebetween. In such a condition,when recording were made by fixed setting of the pulse width and heatingpower of recording pulse series throughout the entirety of the recordingarea of the pigment-type optical disk, the following problem wouldoccur: Excess or insufficiency would occur for a preliminary heating bythe head heating pulse, the modulation degree of RF signal would not beuniform, and the asymmetry of the RF signal would become larger as therecording line velocity becomes higher (for the outer zone). Moreover,the optimum value of the pulse width of the tail heating pulse would bechanged, and, thereby, the record mark width would become uneven.

According to the fourth embodiment of the present invention, it becomespossible to attain recording by record marks having uniform signalcharacteristic and low jitter throughout the disk medium in the rangebetween the most inner zone and the most outer zone.

First, as shown in FIG. 24, setting is made for the most inner zone suchthat: the number of heating pulses of the recording pulse series is n−1(n denotes a mark data length); the ratio Ttop of the pulse width of thehead heating pulse is 1.30 T, each of the ratio Tmp of the pulse widthof each subsequent intermediate pulse and the ratio Ttail of the pulsewidth of the tail heating pulse is 0.65 T, and the optimum recordingpower Pw min (or P min) of the heating pulse is 9.0 mW. These settingvalues are typical numerical values for a pigment-type disk medium, and,may be changed depending on various tuning and/or recording materialthereof.

Then, as shown in FIG. 24, as the recording line velocity increases, theratios Ttop and Ttail are made increased, and, also a ratio of recordingpowers “σ=Pw/P min” is made increased. Thereby, the optimum heatingenergy is applied for a head portion and a tail portion of each recordmark, and, also, the optimum recording power is applied, for recording.Thereby, it is possible to make the width of marks uniform, and, also,the jitter characteristic can be kept non-problematic.

Thus, when the recording line velocity changes as the radial position onthe disk changes according to the CAV recording control scheme,satisfactory recording performance can be ensured by updating thesesetting values, as follows:

Namely, the pulse width ratio Ttop of the head recording pulse withrespect to the recording clock period is changed from 1.30 T (≈49.7(ns)) at the most inner zone to 1.45 T (≈22.8ns) at the most outer zone.Thus, change is made by total 0.15 T.

Furthermore, the pulse width ratio Ttail to the recording clock period Tof the tail heating pulse changes from 0.65 T (≈24.8 (ns)) at the mostinner zone to 0.85 T (≈13.3 (ns)) at the most outer zone. Thus, totally,it changes by 0.20 T.

Furthermore, the rear edge of the head heating pulse and the rear edgeof following each intermediate heating pulse are always synchronizedwith the recording clock pulses. Further, the pulse width ratio Tmp ofeach intermediate pulse is fixed as 0.65 T

The recording power is updated such that: the ratio σ (=Pw/P min) of therecording power Pw at the relevant radial position (for the relevantrecording line velocity) to the optimum recording power P min of theheating pulse at the most inner zone (namely, for the minimum recordingline velocity) is updated and changed from 1.0 to 1.50. Thus, totally,the ratio p is changed by 0.50 according to the radial positioncorresponding to the increase in recording line velocity so that it maybecome larger.

FIGS. 25A, 25B and 25C comparatively show light-emission waveforms ofthe thus-set recording pulses at the most inner zone and most outer zonetogether in such a time scale that the periods of the recording channelclock pulses are caused to be equal to one another.

Each setting value will now be described in detail. When recording ismade at different recording line velocities on the pigment-type opticaldisk, generally speaking, the recording power is approximatelyproportional to the squire root of the recording line velocity, as wellknown, for example, see Japanese Laid-Open Patent Application No.10-106008 mentioned above.

That is, the recording power Pw is calculated by

Pw=Klv{square root over (Lv)}

where Lv denotes the recording line velocity, and Klv denotes aconstant. However, in order to optimize all the setting values includingthe above-mentioned pulse width ratios Ttop and Ttail, and the recordingpower ratio σmax=Pw max/Pw min (the ratio of the recording power Pw maxfor the maximum recording line velocity at the most outer zone to theminimum recording line velocity at the most inner zone), according tothe recording line velocity, the recording powers obtained from theabove-mentioned recording-power ratio σ obtained from linearapproximation with the following formula have proper values for therecording line velocities throughout the recording zone of the opticaldisk:

σ=Klv×Lv+Kpw

where Kpw denotes a constant.

Furthermore, for the ratios Ttop and Ttail, the optimum setting valuescan be obtained according to the recording line velocity throughout therecording zone of the disk by using the setting value calculated throughsimilar linear approximation. Specifically, the following approximationformulas are used:

Ttop=0.030×Lv+1.195

Ttail=0.036×Lv+0.544

Pw=Pw min×σ=Pw min×(0.100×Lv+0.650)

Instead of using these formulas with respect to the recording linevelocity, it is possible to set and update the recording pulses as afunction of the radial position on the disk, or to update the sameaccording to addresses obtained by the preformat information of thedisk. Thereby, it becomes possible to calculate the optimum settingvalues with respect to any recording line velocity by theabove-described method through simple calculation, according to thefourth embodiment of the present invention.

A combination of the recording pulse series according to the CAVrecording control scheme is not limited to the above-described one.Other than it, the basic concept of the fourth embodiment of the presentinvention may be applied to a case where, as being applied for CD-Rdisk, the front edge position and rear edge position of a singlerectangle wave pulse which is not a multi-pulse series but a headportion is emphasized are corrected according to a mark length, a casewhere, as being applied for DVD-R disk, both the edge positions at thefront and rear of the head heating pulse are corrected, and so forth.Specifically, in each of the above-mentioned cases, the setting may befinely optimized with respect to the recording line velocity in asimilar manner. However, in contrast thereto, according to the fourthembodiment of the present invention, the front edge position of the headheating pulse and the rear edge position of the tail heating pulse aremade to be changed as described above as shown in FIG. 25C, and,thereby, control can be simplified.

In more detail, as shown in FIGS. 26A and 26B, recording is made on thetrial writing zone provided at the most inner position of the opticaldisk medium while the recording power is changed by a plurality steps,as in the previously described embodiments, and an optimum recordingpower is determined such that the characteristic values obtained fromthe respective reproduction signals may have satisfactory values.Moreover, trial writing at the maximum recording line velocity can alsobe performed, and thereby, a basic approximation formula for therecording power with respect to the entire zone of the optical diskaccording to the CAV recording scheme may be calculated.

Specifically, two types of optical disks will now be described indetail.

First, in a case of a pigment-type optical disk, as the characteristicvalue of the reproduction signal, 3T modulation degree (asymmetry: Asy.)is preferably employed as the characteristic value of the reproductionsignal, and, “Asy.=0” is determined as the optimum detection value. Asshown in FIG. 26A, ‘asymmetry’ is a value obtained through normalizationof a difference between the average level on the longest data amplitudeof the RF signal and the average level on the shortest data amplitudethereof by the longest data amplitude, and shows the asymmetry betweenthe mark length and space length. In case of EFM pulse modulation,${Asymmetry} = \frac{\frac{I_{14H} + I_{14L}}{2} - \frac{I_{3H} + I_{3L}}{2}}{I_{14H} - I_{14L}}$

where I_(14H) denotes a 14T space level, I_(14L) denotes a 14T marklevel, I_(3T) denotes a 3T space level, I_(3L) denotes a 3T mark level.According to the fourth embodiment, the optimum recording power (Pmin=9.0 (mW)) for the most inner zone is thus calculated, which is thenchanged into the optimum recording power (P max=13.6 (mW)) for the mostouter zone, as the above-described ratio σmax is increased into 1.50.Moreover, according to OPC in the present embodiment, by a plurality ofrecording powers, as shown in FIG. 26A, recording-power dependency ofthe asymmetry is detected. Accordingly, an asymmetry approximationformula of “Pw=0.9×Asy.+5.9” is calculated, in the case of recordingpowers shown in FIG. 26A. Further, as will be described later, bydetecting a shift of asymmetry, it is possible to calculate a shift ofthe recording power ΔPw by using the above-mentioned approximationformula.

In a case of a phase-change type optical disk, as the characteristicvalue of the reproduction signal, 14T modulation degree (Mod.) ispreferably employed, and, “Mod.=0.65” is determined as the optimumdetection value. As shown in FIG. 26B, Mod. is a value obtained throughnormalization of the longest data amplitude of the RF signal by themaximum level on the longest data, and shows a relative ratio ofreflectance difference between the mark and space on the maximum lengthdata. In case of EFM pulse modulation,${Modulation} = \frac{I_{14H} - I_{14L}}{I_{14H}}$

where I_(14H) denotes a 14T space level, and I_(14L) denotes a 14T marklevel. With regard to the optimum recording power for the phase-changetype optical disk, a γ method may be used in many cases in which arecording power Pt such that an inclination γt of a target Mod. changemay be obtained is multiplied by a constant pt, and, thus, the optimumrecording power is obtained. However, description thereof is omitted.Moreover, all the other drawings illustrating the fourth embodimentillustrate the pigment-type optical disk.

Moreover, according to OPC in the present embodiment, by the pluralityof recording powers, as shown in FIG. 26B, recording-power dependency ofthe Modulation is detected. Accordingly, a Modulation approximationformula of “Pw=8.8×Mod.²+8.9×Mod.+3.1” is calculated, in the case ofrecording power shown in FIG. 26B. Further, by detecting a shift ofModulation during recording, it is possible to calculate a shift of therecording power ΔPw by using the above-mentioned approximation formula.In fact, actually measured values well coincide with the thus-calculatedquadratic approximated values.

A specific processing method of the above-described scheme according tothe fourth embodiment of the present invention will now be described.

Generally, a groove for acquiring a tracking error signal (push pullsignal) is formed onto a recording disk such CD or DVD, and a wobblesignal is recorded by bending the groove in a zigzag manner. This wobblesignal is detected by a programmable BPF for various recording linevelocities, and, therefrom, coded information such as that coded byfrequency modulation or phase modulation is restored. Accordingly, evenfrom a non-recorded disk, address information and disk informationunique to the disk can be obtained. A method by which theabove-mentioned information may be generated from a slit-likeintermittent pit formed in a land (LPP: Land-Prepit signal) is alsoknown.

Especially, according to a wobble scheme by a phase modulation in DVD,it is possible to set the frequency thereof to very high, and, withregard to the scheme by LPP, it is possible to demodulate from a signalformed into a minute figure equivalent to a data length. Accordingly,highly precise position detection is possible with respect topre-addresses given to the disk. Therefore, it becomes possible toconnect and record on the terminus part of a last record at an accuracyof approximately ±5T by detecting and demodulating this preformatinformation, even in case where record data is added to follow the lastrecord, or interrupting record and resuming is performed.

From the preformat information employing a low-frequency-band wobblesignal which is different from a recording data band as in CD-R orCD-RW, it is difficult to connect to the terminus part of a last recordat sufficiently high accuracy. Accordingly, in this case, a recordingclock signal is generated by PLL with reproduction of the alreadyrecorded immediately preceding data, and also, a recording clock signalis generated from the wobble signal, thereby, the clock signal to beused beings switched at a time the target address is reached from thealready reached data. Thereby, it becomes possible to add record data soas to follow a last record or to interrupt record and resume. Therefore,even in a case where a lot of data is recorded together in awrite-at-once manner, it is possible to perform recording withoutcausing any problem for reproduction data, by resuming and addingrecording data so as to follow as mentioned above after interruptingrecording.

In the fourth embodiment of the present invention, as shown in FIG. 28,in case where a plurality of recording zones separate concentrically areset, it is possible to use a well-corrected optimum recording power foreach recording zone according to the method as will now be described,and, to attain recording such as to provide jitter characteristic whichis uniform throughout the disk recording area and non-problematic.

The information recording method in this fourth embodiment of thepresent invention will now be described with reference to FIG. 29. Theabove-described recommended setting values of the recording pulse widthsfor a plurality of recording line velocities including the minimum (mostinner) recording line velocity and the maximum (most outer) recordingline velocity, and intermediate recording line velocity, and therecommended setting values of the recording powers or the ratio ρmax ofthe recording powers (the ratio ρ in recording power between those forthe inner and outer zones) are read from the preformat information ofthe optical disk medium 401 (in a step S401). The optimum recordingpowers are newly reset by using the result of trial writing (OPC) on theminimum (most inner) recording line velocity and the maximum (mostouter) recording line velocity by the information record apparatus 401(S402).

Next, the basic approximation formula (first approximation formula) forrespective pulse widths and recording powers with respect to therecording line velocities for the entire recording area of the opticaldisk medium 401 is derived so that the setting values may be calculated(S403). The recording area of the recording medium 401 is divided asshown in FIG. 28 corresponding to the data amount to be recorded, and,an address range for each recording zone is calculated individually(S404).

Then, an interval of updating the pulse width and recording powersetting values for a first recording zone (most inner first recordingzone), and an address range corresponding thereto are determined, and,then, the pulse width and recording power setting values for the firstrecording zone are calculated for updating (S406). Then, while recordingis performed by actual CAV control, the current address is read from thepreformat information (S407), and it is determined whether or not theread address is within a range in which the setting value is retained(S408). When it is not within the range (N of S408), the newlycalculated setting values are used for updating the current values (S406and S407). Thereby, it is possible to perform recording continuouslyacross different recording zones. When the current address is within therange (Y of S408), the recording is performed by CAV control asdescribed above. The same processing is repeated until the end addressof the current recording zone is reached (S409).

Next, after recording onto the current recording zone is completed, theend track of this recording zone is jumped back to, and reproduction isperformed thereon. Therefrom, asymmetry detection is performedimmediately (S410). Thereby, it is determined whether or not the recordmarks have been formed by the optimum recording powers. Specifically,the determination is made by a difference ΔPw from the optimum recordingpower calculated by the OPC according to the above-mentionedrecording-power dependency (Asy or Mod approximation formula) (S411).When the determination result is no good (N of S411), the basicapproximation formula is corrected by the amount of ΔPw (S412). Thus, byusing the thus-corrected basic approximation formula (referred to as asecond approximation formula, henceforth) for setting the recordingpowers, the same operation is repeated for the subsequent recording zone(S405 through S410).

When the above-mentioned determination result is good (Y of S411), thesame operation is repeated for the subsequent recording zone still usingthe basic approximation formula (first approximation formula) forsetting the recording power (S405 through S410).

Then, the same processing (S405 through S413) is repeated until the endaddress for the data to be recorded is reached, recording is performedby CAV control as described above, and, after the end address is reached(S413), the current processing is finished.

By applying such a recording method, a load needed for controlmanagement for recording pulses borne by the controller can beeffectively reduced.

Thus, in actually recording a lot of data all over the optical diskmedium 401, as shown in FIG. 30, the characteristic value of thereproduction signal is detected for each recording zone, and recordingis performed with correction of the approximation formula. Thereby, evenwhen the sensitivity varies throughout the recording area of the opticaldisk medium 401, and/or change in recording power occurs due totemperature characteristic and/or mechanical shift in the recordingapparatus, or the like, the recording power can be approximatelycorrected into the currently optimum one, and, thereby, it becomespossible to perform recording throughout the optical disk medium 401with satisfactory recording performance. Especially, for the diskperipheral (most outer) part, if recording were made only by using theapproximation formula of the recording power obtained from the trialwriting, jitter characteristic would get worse and exceed a permissiblevalue in a time of reproduction due to a large recording power error(indicated by broken lines in FIGS. 27A and 27B). In contrast thereto,according to the present invention, as the approximation formula iscorrected as described above, as shown in solid lines of FIGS. 27A and27B, the allowable level of the jitter is not exceeded at all. Thus,according to the fourth embodiment of the present invention, while afixed jitter level can be not exceeded, recording can be performed withchange in 14T modulation degree (Modulation), 3T modulation degree(Resolution), or Asymmetry being well controlled.

The approximation formula for setting the recording power should becalculated according to characteristics of the optical disk medium 401as described above, and, for this purpose, another manner, for example,linear approximation, or another polynominal approximation formula mayalso be used. The approximation formula thus obtained for the settingvalues are used according to the relevant recording line velocity.Therefore, the relevant recording line velocity should be determinedfrom the address information obtained from demodulation of theabove-mentioned wobble signal or LPP signal. In fact, specific addressesare predetermined for the range between the most inner position and mostouter position, and have correspondences with the recording linevelocities to be used.

With reference to FIG. 31, an information recording apparatus in thisfourth embodiment of the present invention for recording on the opticaldisk medium 401 according to the above-described method will now bedescribed.

First, while a rotation mechanism 403 containing a spindle motor 402which carries out rotation drive of this optical disk medium 401 isprovided. An optical head 404 including a light source, such as asemiconductor laser, an objective lens, and so forth, is provided, forapplying laser light to the disk medium 401, while the head 404 canperform seeking operation along a disk radial direction. Aservomechanism 405 is connected to an objective lens driving device andan output system of the optical head 404.

Moreover, a reproduction signal detection part 406 performingreproduction operation, calculating the modulation degrees orasymmetries and so forth from the reproduction signal detected by thelight-receiving device of the optical head 404 is provided. A wobbledetection part 408 containing a programmable BPF 407 is connected to theservomechanism 405 and the reproduction signal detection part 406.

An address demodulation circuit 409 which demodulates addresses from thedetected wobble signal is connected to the wobble detection part 408. APLL synthesizer circuit 410 is provided in a recording clock generationpart 411 which is connected with the address demodulation circuit 409. Adrive controller 412 is connected to the PLL synthesizer circuit 410.The rotation mechanism 403, servomechanism 405, the reproduction signaldetection part 406, the wobble detection part 408, and the addressdemodulation circuit 409 are also connected to this drive controller 412which is connected to the system controller 413.

Moreover, a system controller 413 has a recording power calculation part414, and, is connected to an EFM encoder 415, and to an LD controllingpart 416 acting as a laser light source controlling part. This LDcontrol part 416 contains an edge signal generation part 418 describedlater besides a recording pulse series generation part 417 whichgenerates a heating multi-pulse control signal containing theabove-mentioned head heating pulse and tail heating pulse.

An LD drive part 420 which is a driver circuit as a laser light sourcedrive part to make the semiconductor laser in the optical head 4 driveby switching respective sources 419 of driving currents for therecording power Pw and bias power Pb is connected to the output side ofLD control part 416.

In such a configuration, the central frequency of the BPF 407corresponding to the recording line velocity is set to the programmableBPF 407 by the drive controller 412. Then, while carrying out addressdemodulation by the address demodulation circuit 409 from the wobblesignal detected by the wobble detection part 408, the recording channelclock signal for each recording line velocity is generated by the PLLsynthesizer circuit 410 having the basic clock frequency thereof changedby the drive controller 412, and it is provided to the recording pulseseries generation part 417.

In order to generate the recording pulses from the semiconductor laser,the recording channel clock signal and the EFM data which is recordinformation are respectively input into the recording pulse seriesgeneration part 417 from the recording clock generation part 411 and theEFM encoder 415, and the recording pulse control signals for therecording pulses which contain the head heating pulse, tail heatingpulse, and intermediate heating multi-pulse series are generated by therecording pulse series generation part 417.

The respective sources 419 of driving currents for the recording powerPw and the bias power Pb are appropriately switched by the LD drive part420. The semiconductor laser is made to emit light by the bias power Pbcorresponding to reproduction power constantly by the source of biascurrent at a time of recording, and, a laser light-emission waveform ofthe recording pulses as shown in FIG. 23C is provided from the recordingpulse control signal generated in the above-mentioned recording pulseseries generation part 417.

In this embodiment, as a front edge signal generation part for the headheating pulse, in the edge signal generation part 418, a multi-stagedelay circuit having a delay amount of approximately 0.5 ns employinggate devices is provided. There, after being input into an edge selectorhaving a configuration of a multiplexer, the recording pulse controlsignal (front edge signal) for the head heating pulse which controls thefront edge position by the edge pulse selected by the system controller413 is generated. Similarly, a multi-stage delay device having a delayamount of approximately 0.5 ns employing gate devices is provided, in anedge signal generation part in the edge signal generation part 418 whichcontrols the rear edge position of the tail heating pulse. There, afterbeing input into an edge selector, the recording pulse control signal(rear edge signal) for the tail heating pulse is generated by the edgepulse selected by the system controller 413.

Such a configuration determines each setting value as described above,the optimum edge pulse is selected for a relevant recording linevelocity, and thus, the proper recording pulse is generated. As therecording pulse generated by this configuration is updated atpredetermined intervals, each setting value changes as shown in FIG. 24.Further, in case the multi-stage delay device is used, during aninterval between successive updating, each pulse width is fixed, and, asthe recording channel clock signal changes, the ratio of the pulsewidths and duty are changed accordingly.

As another example of this embodiment, instead of the multi-stage delaydevices for the head heating pulse and tail end heating pulse in theedge signal generation part 418, a pulse edge generation part having aPLL configuration emptying a phase comparator, a loop filter, a VCO(voltage controlled oscillator), and a frequency divider may be used. Inthis configuration, the frequency of the recording channel clock signalis multiplied by 20, and, the thus-obtained high-resolution clock signalis generated by the PLL, and, thus, the pulse edge signal has aresolution of 0.05T, i.e., approximately in a range between 1.9 ns and0.8 ns. After this multi-stage pulse edge signal is input into an edgeselector having a multiplexer configuration, the front edge signal whichcontrols the front edge position of the head heating pulse by the edgepulse selected by the system controller 413 is generated. Similarly, apulse edge generation part of a PLL configuration is provided in an edgepulse generation circuit of the edge signal generation part 418 whichcontrols the rear edge position of the tail heating pulse. There, afterbeing input into an edge selector, the rear edge signal which controlsthe rear edge position of the tail heating pulse is generated by theedge pulse selected by the system controller 413.

By such a configuration, each setting value is determined as describedabove, the optimum edge pulse is selected for each recording linevelocity, and thus, a desired recording pulse is generated. In case thethus-generated recording pulse is updated at predetermined intervals,each setting value changes stepwise in a saw-teeth manner. Then, in casethe edge pulse generation part of PLL configuration described above isused, each of the ratios of the pulse widths Ttop and Ttail are fixedeven the recording clock signal changes in frequency changes during aninterval between successive updating.

According to the fourth embodiment of the present invention, for any ofthese configurations, uniform recording is possible at a time of CAVrecording, and various circuit configurations may be used for therecording pulse generation part. Thus, according to the fourthembodiment of the present invention, recording according to CAV controlincluding updating of setting values of the ratio of pulse width of thehead heating pulse Ttop, the ratio of the pulse width of the tailheating pulse Ttail, and the recording power ratio σ can be performed,by a simple and small-scale circuit configuration.

As described above, after trial writing (OPC) at the minimum recordingline velocity and the maximum recording line velocity using the trialwriting zone of the optical disk medium 401 is performed, reproductionsignal detection part 406 connected to the optical head 404 detects the3T and 14T mark and space levels of the RF signal, and the asymmetry orthe degrees of modulation (Modulation), and the approximation formulasthereof are calculated by the system controller 413. Then, the systemcontroller 413 calculates the basic approximation formula (firstapproximation formula) for each pulse width and recording power for therecording line velocity, divides the recording area into a plurality ofrecording zones according to data amounts to be recorded, and calculatesaddress ranges for the respective recording zones individually.

The interval of updating the pulse width and recording power settingvalues for the first recording zone (the most inner recording zone), andthe corresponding address range are allocated, and the pulse widths andrecording powers are calculated for the updating interval in the firstrecording zone. While performing recording according to CAV control, theaddress demodulation circuit 409 reads the current address from thepreformat information of the disk 401, and, it is determined whether ornot it is within the range of updating the setting values, i.e., theaddress range, by the system controller 413. When the current address isout of the updating range, the newly calculated setting values are set,and recording is performed continuously.

Immediately after completing recording onto the current recording zone,recording operation is once interrupted under control by the systemcontroller 413. Then, by a tracking servo unit contained in theservomechanism 405, the last track of the recording-finished recordingzone is jumped back to, and reproduction is performed thereon. Then,therefrom, detection of the asymmetry or the modulation degree(Modulation) is performed by the reproduction signal detection part 406.Next, by the recording power calculating part 414 of the systemcontroller 413, from the recording-power dependency (through theabove-described Asy or Mod approximation formula) in the OPC, adifference from the optimum recording power ΔPw is calculated. Then, bythe amount of ΔPw, the basic approximation formula for setting therecording power is corrected for the subsequent recording zone.

By using the thus-obtained approximation formula (referred to as asecond approximation formula) for setting the recording power, undercontrol by the system controller 413, recording operation is restartedfrom the starting edge part of the subsequent recording zone, and, then,the same operation is repeated. Thereby, the modulated data of therecording information can be continuously recorded across the terminuspart of each recording zone and the starting edge part of the subsequentrecording zone.

As shown in FIG. 32, an application of each of the above-describedembodiments of the present invention to a general-purpose computer suchas a personal computer 421 will now be described. This computer 421includes an DVD-R drive 423 besides a 3.5-inch-type FD drive 422 builttherein. The DVD-R drive 423 acts as the information recording apparatusaccording to the above-described relevant embodiment of the presentinvention.

Since the information recording apparatus 423 is built in the personalcomputer 421, when information is recorded into an optical disk mediumby using the recording pulse series which includes the head heatingpulse and successive heating pulses containing the tail heating pulse,while the optical disk medium is rotated, it is possible to performrecording onto the optical disk medium with signal characteristicuniform throughout the recording area thereof according to the CAVmanner, while the compatibility with the conventional recording formatfor media only for reproduction is maintained, without performingvariable velocity control of the rotation speed of the optical diskmedium.

Especially in case a lot of data is recorded on the optical disk medium,the optical disk medium may be divided concentrically into a pluralityof recording zones in consideration of difference between the datatransfer rate from the personal computer body 421 to the informationrecording apparatus 423 and the data recording rate of the informationrecording apparatus 423 itself, and thus, control should be made suchthat recording operation is interrupted and resumed across thethus-divided different recording zones. Even in such a case, throughoutall over the optical disk medium, recording with uniform signalcharacteristic can be performed, and, thus, the information recordingapparatus 423 can be effectively used together with the personalcomputer body 421.

Further, the present invention is not limited to the above-describedembodiments, and variations and modifications may be made withoutdeparting from the scope of the present invention.

The present application is based on Japanese priority applications Nos.2000-360017, 2000-362367, 2000-348777 and 2001-003409, filed on Nov. 27,2000, Nov. 29, 2000, Nov. 15, 2000 and Jan. 11, 2001, respectively, theentire contents of which are hereby incorporated by reference.

What is claimed is:
 1. An information recording apparatus of performing optical recording onto a recording medium with a record mark by using a light beam modulated in a manner of recording pulse series, comprising: a clock frequency change part changing a recording clock frequency according to a recording line velocity so as to make a recording line density uniform; and a recording power calculating part calculating a recording power in accordance with the change in recording line velocity by using an approximation formula, wherein: a recording area of the recording medium is concentrically divided into a plurality of recording zones; an end portion of record data recorded on a recording zone of the plurality of recording zones is reproduced; from a signal characteristic obtained from a thus-obtained reproduction signal, the approximation formula is corrected so that an ideal signal characteristic may be obtained; and the thus-corrected approximation formula is used for determining the recording power for recording onto a subsequent recording zone.
 2. The apparatus as claimed in claim 1, wherein: trial writing is performed onto the recording medium for at least one of the minimum recording line velocity and maximum recording line velocity with plurality of recording powers; the optimum recording power is calculated from signal characteristics obtained from thus-obtained reproduction signals; the optimum recording powers for both the minimum and maximum recording line velocities obtained from either the trial writing or disk information previously recorded onto the recording medium are used, and a first approximation formula for obtaining the recording power with respect to the recording line velocity is calculated; the first approximation formula is used for recording onto a most inner recording zone of the recording medium; and an end portion of record data thus recorded on the most inner recording zone of the plurality of recording zones is reproduced; from a signal characteristic obtained from a thus-obtained reproduction signal, the first approximation formula is corrected so that an ideal signal characteristic may be obtained; and the thus-corrected-approximation formulas are used for determining the recording powers for recording onto subsequent recording zones.
 3. The apparatus as claimed in claim 1, wherein the recording medium comprises a pigment-type recording medium employing a pigment material as a recording layer thereof.
 4. The apparatus as claimed in claim 1, wherein the recording medium comprises a phase-change-type recording medium employing a phase-change material as a recording layer thereof.
 5. The apparatus as claimed in claim 1, wherein modulation or asymmetry is calculated from the reproduction signal and is used to correct the approximation formula.
 6. An information processing apparatus having the information recording apparatus claimed in claim 1 built therein. 